Human Anatomy Human Anatomy

Levels of Organization Levels of Organization Cells Tissue Organ Organ

System

Smallest Unit of

Life

A group of cells working together

A group of

tissues working together

A group of

organs working together

4 Types of Body Tissue4 Types of Body TissueMuscle tissue- composed of cells that

contract. ◦Movement is the result of muscle tissues

contracting in a coordinated fashion Nervous tissue- contains cells that

receive and transmit messages in the form of electrical impulses

Epithelial tissue- layers of cells that line or cover all internal and external body surfaces ◦Often provides a protective barrier ◦Your skin is epithelial tissue

4 Types of Body Tissue4 Types of Body TissueConnective tissue- binds, supports,

and protects structures in the body ◦Most abundant and diverse type of

tissue ◦Includes Bone, Cartilage, Tendons,

Fat, and Blood ◦Connects or holds things together,

such as groups of muscles ◦Characterized by large cells that are

embedded in large amounts of an intercellular substance called matrix

Body Systems: (YOU WILL Body Systems: (YOU WILL NEED YOUR BOOK FOR THE NEED YOUR BOOK FOR THE DIAGRAMS)DIAGRAMS)When organs

work together to complete a specific task, it is called an Organ System

There are many organ systems in your body:

◦ Skeletal◦ Circulatory◦ Muscular◦ Respiratory◦ Integumentary(skin)◦ Reproductive◦ Digestive◦ Endocrine◦ Immune◦ Excretory◦ Nervous

Body Cavities (p. 910)Body Cavities (p. 910)When discussing organ systems, many of them

are located in “compartments” in the body called cavities.◦ Cranial cavity: contains the brain◦ Spinal cavity: surrounds the spinal chord◦ Thoracic cavity: contains heart, lungs and

organs of the respiratory system◦ Abdominal cavity: contains organs of

digestive system Diaphragm: separates abdominal and

thoracic cavity◦ Pelvic cavity: contains organs of

reproduction and excretion

Skeletal Skeletal This system

provides support for the entire body

Ribs protects our vital organs-like your heart and lungs

The spine is the central support for the body.

The longest bone in your body is your femur

Skeletal Skeletal Your hands and

feet are so flexible because they are made of MANY bones:◦ Each foot has 26

bones, while each hand has 27 bones

◦ That means that over half your bones are found in your hands and feet!!!

Skeletal (p.911) Skeletal (p.911) Axial Skeleton

◦skull, rib cage, spine (backbone), sternum

Appendicular Skeleton◦arms, legs,

pelvis, scapula, and clavicle (shaded in on picture)

Joints (p. 915) Joints (p. 915) The place where two bones

meet is called a jointFixed joints: prevent

movement. Often connective tissue is located in a fixed joint to absorb impact.Example: skull

Semimovable joints: give limited movement. Generally allow enough movement to absorb shock or impactExample: spinal chord

Moveable joints: allow a wide range of motion.Example: knees,

shoulders

Joints (p. 916)Joints (p. 916) Joints that are subject to a lot of

pressure (like your knees) are cushioned and protected from friction (which would damage the bones) by cartilage and synovial fluid (also called synovial sac). They connect to the bone with ligaments◦ Cartilage: connective tissue

located between moveable bones. Acts as a surface to reduce friction and wear.

◦ Ligaments: tough connective tissue that hold the bones of a joint in place

◦ Synovial fluid : fluid secreted that lubricates the bones of the joint to reduce friction and wear

JointsJointsTwo painful conditions can

exist at the joints:◦Rheumatoid arthritis:

immune system attacks the body at the joints. Causes inflammation, swelling and stiff joints

◦Osteoarthritis: cartilage begins to wear thin. The bones begin to rub together and causes severe discomfort

Bone anatomy (p. 912) Bone anatomy (p. 912) While your bones are hard

on the outside (compact bone and periosteum), they are soft on the inside (spongy bone).◦ Periosteum: tough

membrane that covers the surface of the bone (where a lot of nerves are)

◦ Compact bone: located beneath the periosteum.

You’re hard bone is stronger and lighter than steel!!

Bone anatomy (p.912) Bone anatomy (p.912) Beneath compact bone is an area of

connective tissue called spongy bone or soft tissue called bone marrow.◦ Spongy bone: strong bone

lattice that is located at points of physical stress

◦ Bone marrow: serves as a production center for blood cells or an energy reserve Red bone marrow: produces

red blood cells, white blood cells, platelets (blood cells don’t have nuclei to perform mitosis)

Yellow bone marrow: mostly fat cells that serve as an energy reserve

Internal structure of compact Internal structure of compact bone (p. 913) bone (p. 913)

The structure of bone material◦Bone is made primarily of cylindrical pieces

made of mineral and protein called lamellae When young, your bones are made of cartilage

that eventually harden to bone (ossification)

◦In the central cylinder of the lamella is a channel called the Haversian canal These channels are where the blood vessels

bring nourishment and carry away wastes.

◦Surrounding each Haversian canal is a layer of proteins and bone cells (osteocytes)

Muscular Muscular

Muscles are responsible for your body's every move.

There are 3 types of muscles:◦Skeletal◦Smooth ◦Cardiac

Skeletal MuscleSkeletal MuscleSkeletal muscles move and support the

skeleton.There are 640 individually named skeletal

muscles. When these muscles contract or shorten,

your bone moves. Skeletal muscles are voluntary muscles

(which means we can consciously control them)

Composition of skeletal Composition of skeletal muscle (p. 919)muscle (p. 919)

Skeletal muscle is made of cells called muscle fibers◦Muscle fibers have many nuclei and are

separated by bands called striationsMuscle fibers are gathered in groups

called fasciclesMuscle fibers are made of the

following:◦Myofibrils◦Myosin◦Actin

Composition of skeletal Composition of skeletal muscle (p. 920)muscle (p. 920)

Myofibrils are threadlike structures that make up a muscle fiber◦They are made of 2 proteins that enable

a muscle to contract Myosin: Thick protein fibers that mesh with

actin proteins Actin: Thin protein fibers that overlap with

myosin proteins Each actin-myosin bundle is bordered by an

area called a Z line. This region from one Z line to the next is

called a sarcomere

Contraction of muscleContraction of muscleThere is a “head” on myosin that fits into “grooves”

created by actinWhen a muscle contracts the myosin “head” pulls

the actin strand and shortens itThe “head” can then move to another “groove” in

the actin to continue to shorten the actin strandThis process requires ATP If you work out hard, you don’t have enough oxygen

to go through the Kreb’s cycle . . . oxygen debt◦ Your muscles begin to run out of ATP (muscle

fatigue)◦ You must go through lactic acid fermentation (this

is why your muscles get sore . . . lactic acid build up)

Contraction of muscle (p. Contraction of muscle (p. 921)921)Most muscle are arranged as

opposite pairsMuscles always pull bones, not push

them so you need to be able to contract in two different directions◦Flexor bends the joint to flex the limb

(biceps pull your arm in)◦Extensor flexes to straighten the limb

(triceps allow you to straighten your arm)

Connectors (p. 916)Connectors (p. 916)Ligaments-connect bone to bone

Tendons-connect muscle to bone◦Origin: where a muscle attaches to

a stationary bone◦Insertions: a muscle attaches to a

mobile bone

Smooth MuscleSmooth Muscle Smooth muscles are found in the hollow parts of the body.

◦ They are composed of interlacing sheets of muscle cells. Unlike skeletal muscle, they have a single nucleus.

◦ There are no striations in smooth muscle (no severe contractions)

◦ This would be in places like the lining or the stomach (moves food), intestines (moves waste), blood vessels (change the diameter) and the bladder (moves urine).

◦ A smooth muscle is an involuntary muscle (This means that you cannot consciously control this muscle-they just work when needed)

◦ They move things through the body with a wave-like motion (peristalsis)

Cardiac MuscleCardiac Muscle Cardiac muscle makes up the heart (along with blood

vessels) that makes up the cardiovascular system Cardiac muscles contract automatically to squeeze

the walls of the heart inward.◦ They are similar to both skeletal and smooth

muscle. They are striated (so they can contract) They have a single nuclei They are involuntary

◦ The heart beats nonstop about 100,000 times each day.

◦ Cardiac muscles don’t get tired-they work constantly until you die

Integumentary Integumentary This system

includes skin, hair, nails, and various glands

The function of this system is protection-it is a barrier from injury and infection

The glands are responsible for secreting sweat and oils to release waste or cool the body

Subcutaneous layer

Epidermis (p. 925)Epidermis (p. 925)The epidermis is the outermost layer of skin

◦It is composed of an outer (corneal layer) and a lower (basal) layer

◦This outer layer is made mostly of dead skin cells filled with a protein called keratin This makes skin tough and leathery to resist

the outer environment. It also acts as water-proofing

◦Skin color for the epidermis is controlled by the amount of melanin (a brown pigment) Melanin is produced in the dermis

Dermis (p. 925)Dermis (p. 925)Inner layer of the skin composed of living cells and

specialized structures◦Blood vessels◦Sensory neurons◦Hair follicles (hair is made of dead cells filled

with keratin. Oil from glands keep them supple)◦Glands

Sweat glands to cool the body Oil glands to soften skin, prevent water loss,

etc Because the glands produce sweat, the dermis

is responsible for temperature regulation

Subcutaneous layerSubcutaneous layer

A fatty layer beneath the dermis that acts as insulation and storage of energy (fat cells)

CirculatoryCirculatoryThe circulatory

system is made up of the vessels and the muscles that help and control the flow of fluid around the body.

It consists of the cardiovascular system and the lymphatic system

As blood begins to circulate, it heads from the lungs to the heart

CirculatoryCirculatoryCardiovascular

system◦ Heart◦ Blood vessels◦ Blood

Lymphatic system◦ Lymph nodes◦ Lymph vessels◦ Lymph

HeartHeartThe center of the cardiovascular

system is the heartA septum (wall) separates the

heart into 2 sections◦Right side: pumps blood to the lungs (oxygen deficient blood)

◦Left side: pumps blood from the heart to the rest of the body (oxygen rich blood)

HeartHeartEach side of the heart is separated

into an upper and lower chamber◦Each upper chamber is called an atrium You have a left atrium and right atrium (depends on what side of the septum you are)

◦Each lower chamber is called a ventricle You have a left and right ventricle

Movement of bloodMovement of bloodTo control the flow of blood, you

have flaps ( called valves)that only open in one direction◦The valve that controls blood flow

from the right atrium to the right ventricle is called the tricuspid valve

◦The valve that controls blood flow from the left atrium to the left ventricle is called the mithral valve

Blood flow – Part 1 (p. Blood flow – Part 1 (p. 934)934)Deoxygenated blood enters the right

atrium through a vessel called the vena cava◦Superior vena cava comes from above

the heart◦Inferior vena cava comes from below the

heartRight atrium sends the deoxygenated

blood to the right ventricleRight ventricle contracts and sends the

blood through the pulmonary arteries to the lungs

Blood flow – Part 2 (p. Blood flow – Part 2 (p. 934)934)The deoxygenated blood gains oxygen in

the lungs (discussed in the respiratory system)

Oxygenated blood returns to the left atrium through the pulmonary veins

Oxygenated blood is pumped into the left ventricle

Contraction of the left ventricle forces blood up through a large blood vessel called the aorta

The blood is then transported to the rest of the body

CirculatoryCirculatoryIt leaves the

heart from the left ventricle and goes into the aorta.

The aorta is the largest artery in the body.

The blood leaving the aorta is full of oxygen

Blood vesselsBlood vesselsThere are 3 primary blood vessels in the

circulatory system◦ Arteries: largest of the muscular vessels

that carry blood away from the heart Made of several arterioles

◦ Veins: vessels that contain several valves that bring blood to the heart Made of several venules Vericose veins are caused by poor valves

◦ Capillaries: very small blood vessel where gases (ie. oxygen) can diffuse to the body tissues surrounding the capillary.

Blood Vessels: Blood Vessels: Lumen = Lumen = cavitycavity

CirculatoryCirculatoryThe oxygen rich blood travels

throughout the body through arteries◦Arteries are tough, elastic tubes

that carry blood away from the heart.

◦Arteries branch into capillaries(which are the smallest blood vessels with walls only one cells thick)

CirculatoryCirculatory Much of the

gas/nutrient exchange between the blood and body cells occurs in the Capillaries, which eventually lead to veins◦ Body cells get

oxygen from the red blood cells, then give them carbon dioxide (a waste product)

Veins carry the blood to the heart.

Once the blood reaches the heart, it is pumped back into the lungs to expel the carbon dioxide and obtain oxygen

Diseases of the circulatory Diseases of the circulatory systemsystemHypertension: also known as “high blood

pressure”.◦ This places stress on the walls of arteries and run

the risk that blood vessels will burst Stroke can be caused by a burst blood vessel in

the brainHypotension: also known as “low blood pressure”.

◦ Often feels cold because blood is not able to reach the extremities efficiently

Atherosclerosis: when an artery is blocked by a build up of fatty material◦ Increases blood pressure and can lead to a burst

blood vessel

Lymphatic system (p.939)Lymphatic system (p.939)Part of the circulatory system, the lymphatic system

is responsible for returning fluids (lymph) that have collected in the blood stream

Important differences◦ Lymphatic system is one way (not a circuit)◦ There is no pump (like the heart)

Skeletal muscles squeeze fluid through vessels similar to blood vessels

◦ Lymph passes through lymph nodes that act as filters to remove foreign particles, microorganisms or other tissue debris Lymph nodes have specialized cells called

lymphocytes (specialized white blood cells that fight disease and infection)

BloodBloodBlood is made of many different fluids and cell

types◦ Plasma: yellowish fluid that contains about

90% water and many nutrients, wastes, chemical messengers, etc

◦ Red blood cells : (erythrocytes): oxygen binds to the hemoglobin molecule in red blood cells in the lungs. When they reach the cells in body tissues, they give up the oxygen to the cells and pick up carbon dioxide waste through another gas exchange. Hemoglobin: an iron containing protein on

red blood cells

BloodBloodWhite blood cells (leukocytes): cells of the

immune system used to fight disease and infection◦ Phagocyte: white blood cell that engulfs

infectious cells (ie bacteria) and destroys them◦ Antibodies: produced by another white blood cell

that detects infections cells and activates the bodies immune system Antibodies detect different protein markers on red blood

cells. These proteins give us our blood type (A, B, AB, O). If you don’t have an A or B on your red blood cell, your immune system will attack foreign blood with those “antigens”.

Platelets: fragments of larger cells that can bind together at the site of tissue damage (this is what forms a scab)

Respiratory (p. 947)Respiratory (p. 947)The respiratory

system allows us to breathe

The diaphragm is a muscle contracts and relaxes to move air in and out of your lungs

The lungs are the actual site of gas exchange.

Air Pathway (p. 947)Air Pathway (p. 947)Breathing begins at the nose and

mouth◦Small hairs in the nose, mucous, and a

nasal cavity lined with cilia trap many particulates that are swept into the throat to be swallowed.

The air moves to the pharynx, a tube at the back of the nasal cavity and mouth◦The epiglottis is a flap of cartilage that

can close or open. This prevents food particles from going into the lungs

RespiratoryRespiratoryThe nasal cavity and

throat filter, moisten and warm the air we breathe in

Some of the epithelial tissue that line this system has cilia which trap particles that don’t belong and send them up for you to cough out

Some of the cells produce mucous

Air Pathway (p. 947)Air Pathway (p. 947)The air continues down the pharynx to the

trachea, a rigid pipe made of cartilage◦This is again lined with cilia to trap

unwanted particlesThe trachea branches into 2 bronchi made

of smooth muscle and cartilage◦These are also lined with cilia

The bronchi then separate into several tubes in the lungs called bronchioles◦At the end of these bronchioles are

several aveoli. This is what oxygen and carbon dioxide are exchange.

Respiratory (p. 947)Respiratory (p. 947)The trachea joins

the nasal passage and throat to the lungs.

The bottom of the trachea splits into two branches called bronchi. ◦One enters the

right lung and one goes to the left lung.

◦Aveoli are at the end of the bronchi.

Respiratory (p. 947)Respiratory (p. 947)The bronchial

tree's job is to spread the air from the trachea over a very wide area as quickly as possible.

The air travels until it hits little bags called alveoli, where oxygen is absorbed into the blood stream through capillaries and CO2 is released.

Immune Immune The immune

system defends people against pathogens, or any invader in your body.

Through a series of steps called the immune response, the immune system attacks organisms and substances that invade our systems and cause disease.

ImmuneImmuneBefore you are infected by a disease, your body has a first line of defense◦The skin serves as a physical barrier to outside pathogens

◦Mucous membranes secrete mucous which traps pathogens which can be expelled or destroyed by the acid in your stomach

◦Digestive acids in your stomach

Immune Immune Many of the symptoms you feel when you

are sick are the result of your body fighting invaders:◦Lymph nodes swell when your sick

because they are producing more white blood cells

◦Your fever is meant to slow the growth and reproduction of pathogens (invaders) However a fever over 103°F can

denature your proteins◦Mucous secretions and coughing expel

pathogens

ImmuneImmune If a pathogen gets through your first line of

defense, you have another level of protection . . . nonspecific immune response◦ If your body is damaged (cut or other break in

the skin), your body will start an inflammatory response Blood and lymph go to the area of injury

Histamine is released to attract other cells of the immune system, allow more fluids to the area (causes swelling) and begins the blood clotting process with platelets

White blood cells called phagocytes come in and destroy all pathogens and foreign material

ImmuneImmuneYour last line of defense against

pathogens is the immune system (specific immunity)◦This is a specific response aimed at a

specific infection◦This is not an immediate response (this

is why there is a delay between begin exposed to the disease and showing symptoms)

◦The immune cells of the immune system are called lymphocytes or leukocytes

Immune Immune The cells that are

part of this defense system are white blood cells, or leukocytes.

Leukocytes are produced or stored in many locations throughout the body, including the thymus, spleen, lymph nodes and bone marrow.

Immune Immune The immune

system has it’s own transportation vessels which are a part of the circulatory system◦ They are called the

Lymphatic Vessels◦ Lymph fluid can also

travel in the blood vessels

Immune CellsImmune CellsB cells

◦ Made and developed in the bone marrow

◦ Produce antibodies that recognize antigens (any substance that the immune system believes is foreign to the body)

T cells◦ Made in the bone

marrow and developed in the thymus

◦ Helper T cells recognize part of the antigen on the surface of macrophages They call in cytotoxic T

cells

◦ Cytotoxic T cells destroy cells

CELL-MEDIATED IMMUNITYCELL-MEDIATED IMMUNITYBefore an immune response can begin, it must

be activatedIn a cell-mediated immune response, a

macrophage (specialized white blood cell that ingests pathogens) will engulf a foreign substance and present an antigen on its surface

Receptor proteins on T helper cells bind with the antigen and this causes the macrophage to release a substance called interleukin-1 (IL-1)

IL-1 activates the T helper cell and the T helper cell releases a substance called interleukin-2 (IL-2)

CELL-MEDIATED IMMUNITYCELL-MEDIATED IMMUNITYIL-2 stimulates the production of more

T helper cells and activates T cytotoxic cells

The T cytotoxic cells kill all your cells that have the foreign antigen◦Cytotoxic cells destroy your infected cells

and cancer cellsA third type of cell, T suppressor cells are thought to be responsible for shutting down the cell-mediated immune response

HUMORAL IMMUNE HUMORAL IMMUNE RESPONSE –START HERERESPONSE –START HEREThe release of interleukin-2 (IL-2) from the

cell-mediated response also activates B cells

B cells begin to produce antibodies◦B cells that produce antibodies are called plasma cells

◦Antibodies are proteins that specifically bind to the antigen

◦Antibodies work by binding to foreign substances so that macrophages can come in and destroy them, or

◦Inactivate foreign toxins or viruses

HUMORAL IMMUNE HUMORAL IMMUNE RESPONSERESPONSEThe first time that your body responds to an

infection/disease is called a primary immune response◦ It takes your body about a week to build up

enough of an immune response to fight it off (this is when you feel sick)

If you are exposed to an infection/disease again, your body mounts a secondary immune response◦ After a primary immune response, some of your

plasma cells become memory cells that will recognize the foreign antigen

◦ Secondary immune response only takes a few hours (This is why they say you are immune to a disease. The response is so quick you don’t get sick)

VACCINATIONSVACCINATIONSHow do vaccines work?

◦You are injecting just the plasma membrane/cell wall of a pathogen, or

◦An attenuated pathogen (one that has been rendered inactive by heat, but still has the membrane proteins) Your body will create memory cells to those membrane proteins and you will be mounting a very rapid secondary immune response if exposed to the disease again.

PROBLEMS WITH THE PROBLEMS WITH THE IMMUNE SYSTEMIMMUNE SYSTEM

Allergies: a physical response to a common foreign antigen (pet dander, pollen, etc)

Asthma: a foreign antigen causes the respiratory bronchioles to over-react and narrow (reduced airflow)

Autoimmune disease: your immune cells recognize some part of your body as foreign. This causes your immune system to destroy part of your own body

HIV: destroys the cell-mediated immunity of your body. HIV doesn’t kill you. It’s an infection you get after HIV has destroyed your defenses

Gastrointestinal tractGastrointestinal tractThe gastrointestinal tract, or

digestive tract, is responsible for ingesting and breaking down nutrients to be used by the body

It starts at the mouth and ends with the anus

The following is a breakdown of the digestive tract

Digestive SystemDigestive SystemMOUTH

ESOPHAGUS

LIVERSTOMACH

GALL BLADDER PANCREAS

LARGE INTESTINE

SMALL INTESTINE

APPENDIX RECTUM

ANUS

DigestiveDigestive

The food we eat must be broken down into chemicals that the body can use. ◦This whole process is called digestion and that is the function of the digestive system.

DigestiveDigestiveThe first step takes place

in your mouth, where food is broken down into smaller pieces by the mechanical action of your teeth

Your saliva also contains an enzyme, salivary amylase, that breaks down starch (a type of sugar) into simpler sugars

Digestive Digestive After being swallowed,

the food travels down your pharynx to your esophagus, which is about 10 inches long.Since both air and

food travel down the pharynx, a flap of tissue called the epiglottis prevents food from going down the trachea

The esophagus is covered in muscles that push the food to your stomach.

ESOPHAGUS

DigestiveDigestiveThe stomach releases

acids and enzymes that break down the food◦The stomach has

several layers of smooth muscle that aid in the mechanical digestion of food.

◦The stomach also releases gastric fluids to aid in chemical digestion

STOMACH

DigestiveDigestiveAfter food enters the stomach from the

esophagus, the cardiac sphincter closes to prevent food and gastric juices from entering the esophagus◦Food remains in the stomach for 3-4 hours

The smooth muscles of the stomach churn the stomach to mix the food with the gastric juices and form chyme◦Pepsin is a digestive enzyme that works

at low pH◦HCl is the acid released into the stomach

to make sure the pepsin is active

DigestiveDigestiveWhen digestion is finish, the

stomach forces the chyme into the small intestine through the action of peristalsis, wave-like muscle contractions that cause the substance to move

Once in the small intestine, the pyloric sphincter closes to prevent the chyme from returning to the stomach

DigestiveDigestiveThe small intestine is the

final place for digestion It is about twenty feet long

and one inch in diameter. It is made of 3 parts:DuodenumJejunumIleum

It releases more chemicals to break down food

This is also where the nutrients from food are absorbed through small finger-like projections called villi

SMALL INTESTINE

DigestiveDigestiveWaste products and

food that are not absorbed in the small intestine pass into the large intestine (or colon) through perstalsis

The large intestine is only 5 feet long, but is much wider than the small intestine

LARGE INTESTINE

DigestiveDigestiveThe large intestine

removes water from the food waste to create feces

A meal may take up to three days to pass through your digestive system. It spends about three hours in your stomach and up to 20 hours in your large intestine!

Digestive Digestive The pancreas is an elongated

gland that is below the stomach. It has many functions:◦ It releases hormones to control

blood sugar (ENDOCRINE)◦ It can release sodium

bicarbonate to neutralize the stomach acid before chyme enters the small intestine (DIGESTIVE)

◦ Produces many enzymes that help to break down proteins, carbohydrates, lipids and nucleic acids (DIGESTIVE) PANCREAS

Digestive Digestive The Liver :

Stores glucose as glycogen (DIGESTIVE)

Breaks down toxic substances, bacteria and old blood cells (EXCRETORY)

Secretes bile which is necessary to digest lipids/fats (DIGESTIVE)

The extra bile from the liver is stored in the Gall Bladder (DIGESTIVE)

LIVER

GALL BLADDER

Excretory systemExcretory systemWe’ve already discussed how waste

is removed form the gastrointestinal tract through the large intestine and anus

The other major way to remove waste is through the urinary system◦Kidneys◦Ureter◦Urinary bladder◦Urethra

KidneysKidneysResponsible for removing most of

the nitrogenous wastes◦Most nitrogenous waste first goes to

the liver in the form of ammonia◦Ammonia is extremely toxic so the

liver converts into the less toxic chemical urea

Urea is sent into the blood stream where it enters the kidneys for disposal

Excretory – SEE p. 994Excretory – SEE p. 994The kidney is made of several units called

nephrons◦Nephrons are tiny tubes that end in a tight

ball of capillaries called Bowman’s capsule◦The purpose of the nephrons is to filter the

bloodBlood first enters Bowman’s capsule where

nutrients in the blood are reabsorbed while the waste is allowed to pass

The blood continues to flow through the nephron and continues to filter out nutrients and allow the waste to pass

ExcretoryExcretoryThe nutrients reabsorbed during the

filtration process are returned to the bodyThe fluid and waste that remain form

urine and are transported to the ureter, a narrow collecting tube attached to the kidney

Each ureter leads to a storage organ called the urinary bladder

When the waste is ready to be evacuated, muscular contractions force the urine out through a tube called the urethra

Other avenues of Other avenues of excretionexcretionIn addition to excretion through the gastrointestinal tract and urinary system, we have already discussed other avenues of waste removal:◦Lungs: removes CO2

◦Skin: removes wastes, salts and oils in the subcutaneous layer

Nervous Nervous The nervous system is divided

into two main systems:◦The central nervous system (CNS) ◦The peripheral nervous system

Central Nervous SystemCentral Nervous SystemThe spinal cord and the brain

make up the CNS. Its main job is to get the

information from the body and send out instructions.

Central Nervous SystemCentral Nervous SystemThe brain helps to control all of the

body systems and organs, keeping them working like they should. ◦The brain communicates with the rest of the

body through the spinal cord and the nerves.

◦This system also gives instructions to all parts of the body about what to do and when to do it

◦Reflexes are involuntary, self protective movements and are not controlled by your brain (they just go to spinal cord and back)

Anatomy of the brainAnatomy of the brainThe brain is composed of 4 basic parts

◦Cerebrum: The cerebrum is responsible for higher levels of thinking and communication Speech, reasoning

◦Diencephalon: This is the relay center for the brain where information entering or leaving the brain is routed

◦Brain stem: This is responsible for a lot of involuntary responses in the body Heart rate, homeostasis, respiration, sensory

input

◦Cerebellum: Helps to coordinate movement

Spinal cordSpinal cordThe spinal cord is the central

relay between the brain and the rest of the body◦A flexible spine gives protection to

the nervous tissue that makes up the spinal cord

◦Signals are both sent are received via the spinal cord

Peripheral Nervous Peripheral Nervous SystemSystemThe peripheral

nervous system is made up of all of the nerves and the wiring.

This system SENDS the messages from the brain to the rest of the body as electrical signals.

Peripheral Nervous Peripheral Nervous SystemSystemCells of the nervous system are called

neurons◦ Neurons carry messages in the form of an

electrical impulses. ◦ The messages move from one neuron to

another to keep the body functioning. ◦ Unlike other body tissues, nerve cells

cannot also be repaired if damaged due to injury or disease.

Structure of neuronStructure of neuronThe cell body contains the

organelles and nucleus of the cell◦Dendrites are structures that

receive signals from other neurons◦Axons are used to transmit signals

away from nerve

Structure of neuronStructure of neuronThe axon of the neuron is covered in a lipid

layer known as the myelin sheath◦The myelin sheath acts as an insulator

like a rubber cordSchwann cells surround the axon and are

responsible for making the myelin sheath◦Gaps in the myelin sheath are known as nodes of Ranvier

Axons end in an axon terminal with a gap between the next neuron known as a synapse

How do neurons work?How do neurons work?Nerves send signals in the form of

an action potential◦All neurons contain an electrical charge

inside the cell that is different than outside. This difference in charge is called a membrane potential

◦When the charge is changed (by allowing ions into or out of the membrane), you can move a charge along the nerve Change the potential in different spots

How do neurons work?How do neurons work?Resting potential

◦ When the neuron is not sending or receiving a signal, there are more negatively charged proteins and potassium ions, K+, inside the cell and more sodium ions, Na+ outside the cell . . . net negative charge

Action potential◦ When a signal is sent along the neuron, ion

channels allow the sodium ions into the cell (via a concentration gradient) through a sodium channel (facilitated diffusion) . . . net positive charge

◦ This changes the charge of the cell and the signal causes the next cell in line to start an action potential

How do neurons work?How do neurons work?After the action potential, the cell

needs to regain its state of resting potential◦To do this it utilizes the sodium-potassium pump to pump the sodium out of the cell Active transport using ATP

◦During this time, the nerve cannot send another signal and is called the refractory period

Sending a signal between Sending a signal between neuronsneuronsA neuron can only send a signal to

another neuron through the synapseTo do this, a neurotransmitter called

acetylcholine is released from the axon terminal

Acetylcholine travels across the neuron and stimulates the next neuron, muscle or organ that needs to receive the signal

After the acetylcholine has sent the signal, an enzyme called acetylcholine esterase breaks down the acetylcholine

AcetylcholineAcetylcholine

Somatic vs. Autonomic Nervous Somatic vs. Autonomic Nervous System (Peripheral Nervous System (Peripheral Nervous

System)System) Somatic

◦ Called the voluntary nervous system

◦ Motor neurons are the ones that activate different muscles and glands

◦ Allows for conscious control of your muscles and lets you control your movement

◦ There is also an involuntary component involved in reflexes

Autonomic◦ Called the involuntary

nervous system◦ Sympathetic: called

the fight or flight response (increased heart rate, pupils dilate, etc)

◦ Parasympathetic: resting response (decrease heart rate, pupils constrict, etc)

Sensory OrgansSensory OrgansThere are many different sensory

receptors depending on what they detect◦Mechanoreceptor: responds to

movement, pressure and tension◦Photoreceptor: responds to light◦Chemoreceptor: responds to chemicals◦Thermoreceptor: responds to

temperature change◦Pain receptor: responds to tissue

damage

Hearing and balance Hearing and balance (Diagram on p.1017)(Diagram on p.1017)

The outer ear is responsible for “capturing” sound and transmitting it down the auditory canal

The auditory canal leads to the tympanic membrane or eardrum

Sound vibrations (moving air) cause the tympanic membrane to vibrate and move three small bones: the hammer, the anvil and the stirrup

Hearing and balanceHearing and balanceAfter the three bones are set in motion,

the stirrup transfers vibrations to a membrane called the oval window

The oval window leads into the cochlea◦The cochlea has 3 fluid filled chambers that

are separated by membranes◦Vibrations from the oval window cause hair

cells within the fluid of the cochlea to move◦This movement is interpreted and sent by

your auditory nerve to your brain as sounds

Hearing and balanceHearing and balance In addition to hearing, the ears are responsible

for maintaining balance◦ In the middle ear there is a tube connecting to

the throat, Eustachian tube This allows air pressure to equalize on both

sides of the tympanic membrane (popping your ears)

Additionally, in the inner ear, there are 3 fluid filled chambers called the semicircular canals◦ Each canal is situated in one of 3 axis◦ There are mechanoreceptors in the

semicircular canals that can be interpreted as relative position

Vision: Vision: (Diagram on p. 1019)(Diagram on p. 1019)All sight is based on light striking a place

in the back of the eye called the retina◦Light first passes through the cornea, a

protective outer layer of the eye◦Next, light passes through the pupil, or the

opening in the eye that controls the amount of light It contracts when very bright It dilates when dim or when “fight or flight” is

active

◦The muscles that control the pupil are located in the pigmented iris

VisionVision The light that passes through the iris hits the lens

◦ This is a crystalline structure that allows the light to be refracted, bent, to produce a clear image If your lens cannot be properly “bent”, you will

need some sort of vision correction (glasses, contacts)

Again, the muscles in the iris controls the amount of light passing into the eye

Within the retina are specialized photorecptors called rods and cones◦ Rods respond to dim light◦ Cones respond to bright light

The signals that hit the rods and cones are sent by the optic nerve to be interpreted by the brain

Taste and smellTaste and smellMost people perceive taste

because of chemoreceptors located on the tongue, or taste buds◦Taste buds are located between the

bumps on your tongue, papillae◦You have chemoreceptors for:

sweet, salty, sour and bitter◦The signals are sent to the brain to

interpret taste.

Taste and smellTaste and smellSmell works very similar to tasteInstead of chemoreceptors on

your tongue, smell has specialized chemoreceptors in your nasal passages called olfactory receptors◦When a chemical binds to an

olfactory receptor, the information is sent to your brain and interpreted as smell

TouchTouchYou have many mechanoreceptors throughout

the skin◦They are concentrated in the face, tongue and

fingertipsYou have two types of thermoreceptors in the

skin◦Sensitive below 20°C (cold receptor)◦Sensitive between 30°C and 45°C (heat

receptor)You have many types of “pain” receptors

located throughout the skinAll receptors travel to the spinal chord and up to

the brain

Endocrine systemEndocrine system

Endocrine systemEndocrine systemSystem that produce hormones

to regulate body activities◦Hormones are produced by various endocrine and exocrine glands throughout the body Endocrine glands: ductless gland that

secrete hormones into the blood stream or fluids of nearby tissues

Exocrine glands: gland with a tube-like structure that transport substances to specific locations inside or outside the body

HormonesHormonesHormones are chemicals that influence body

activity. They are transported throughout the body using the blood stream and extracellular fluid◦ Amino-acid based hormone: water soluble

hormone Binds to protein receptors on the cell membrane Often the first to trigger a signal in the cell

◦ Steroid hormone: lipid soluble hormone Lipid soluble allows the hormone to enter

through the plasma membrane Causes the cell to activate existing enzymes or

to initiate protein synthesis for specific enzymes

Organs of the endocrine Organs of the endocrine systemsystemHypothalamus

PituitaryThyroidAdrenalGonads

PancreasThymusPinealParathyroidDigestive cells

Hypothalamus/Pituitary: Hypothalamus/Pituitary: List of hormones released (p. List of hormones released (p.

1035)1035)Hypothalamus: “controls” much of the endocrine system◦Located in the part of the brain that

initiates many of the responses of the endocrine and nervous system

◦The hypothalamus often starts the hormone response by sending signals to the pituitary gland Releasing hormones: stimulates the pituitary

gland to release hormones (ON SWITCH) Release-inhibiting hormones: inhibit the release

or production of hormones (OFF SWITCH)

Thyroid Thyroid Thyroid gland: located near the lower part of the

larynx◦ Thyroid hormones help to maintain normal heart

rate, blood pressure and body temperature◦ Also helps to transport calcium from the blood to

the bone to generate bone tissue for healthy bone development and repair

Hyperthyroidism: produce to much thyroid hormone◦ Symptoms include: hyperactivity, weight loss,

high blood pressure, increased heart rateHypothyroidism: do not produce enough thyroid

hormone◦ Symptoms include: lethargy, lack of growth,

weight gain, low heart rate, low body temp

AdrenalsAdrenalsAdrenal glands: one adrenal is located

above each of the kidneys◦Produces epinephrine and norepinephrine (also known as adrenaline and noradrenaline) Initiates fight or flight respons – increased

heart rate and blood pressure, increase blood sugar levels, increase oxygen flow to lungs

◦Also produces cortisol which promotes the cells to produce glucose from proteins This hormone is often released when the

individual is stressed

GonadsGonadsGonads begin producing hormones when the individual hits puberty◦Responsible for the development of secondary sex characteristics

◦Responsible for the maintaining the production or release of the sex cells

PancreasPancreasThe pancreas is important because of its

production of insulin◦ Insulin is responsible for regulating the levels of

glucose available in the blood and available to cells

◦ Diabetes mellitus is a condition where cells are unable to receive blood glucose so there is a high level of glucose in the blood Type 1: The immune system attacks the cells

that produce insulin (usually treated with a daily insulin injection)

Type II: A hereditary condition that is usually triggered by obesity and inactivity (may be treated with diet and exercise)

Thymus / Pineal / Parathyroid Thymus / Pineal / Parathyroid //

Digestive cellsDigestive cellsThymus: produces that hormones that stimulates the maturation of T-cells

Pineal: releases melatonin which helps to regulate sleep patterns

Parathyroid: causes calcium to be transferred from the bone to the blood (opposite of thyroid and must in unison)

Digestive cells: helps to release various fluids during digestion (stomach acid, digestive enzymes, gastric juices)

Homeostasis: How it Homeostasis: How it worksworksThe ability or tendency of an organism or

cell to maintain internal equilibrium by adjusting its physiological processes

In animals such as ourselves, the internal environment of our bodies must have certain conditions within tolerable limits to continue to function properly

Environmental conditions that cause reactions are called stimuli (plural = stimulus)

A feedback mechanism occurs when the level of one substance influences the level of another substance or activity of another organ.

Negative FeedbackNegative FeedbackNegative feedback is where various

receptors and effectors bring about a reaction to ensure that conditions remain favorableIn negative feedback, a final step in a

reaction inhibits the start of another reaction◦ A receptor is a structure that monitors

internal conditions, sense changes, and initiate a response (usually by sending signals to the brain)

◦ Effectors are muscles, organs, or other structures that receive signals from the brain. When an effector receives a signal from the brain, it changes its function in order to correct the change from normal conditions.

Positive FeedbackPositive FeedbackPositive feedback mechanisms are

designed to accelerate or enhance the output created by a stimulus that has already been activated

Push levels/conditions in the body out of normal ranges

When the body senses a change, it increases or accelerates that change

Happens much less often than negative feedback

HomeostasisHomeostasisDepending on the physiological conditions, a

hormone can act as a positive or a negative feedback◦ For example if you release an initial hormone

and it causes subsequent hormones to be released, this is positive feedback Adrenocorticotropic hormone (ACTH):

stimulates the production of cortisol in the adrenals

◦ When a hormone inhibits the release of a hormone, this is negative feedback Release-inhibiting hormones produces by the

hypothalamus prevents the production of hormones in the pituitary