The Human Body

Body Organization

• Organ Systems – groups of organs in the body that work together to form a specific task

• Homeostasis – the maintenance of a constant internal state in a changing environment

THE INTEGUMENTARY SYSTEMskin, hair, and nails

Functions of the Skin

• Protects you by keeping water in the body and foreign substances out

• Sense of touch

• Helps regulate body temperature with sweat glands

• Gets rid of waste

• Largest organ of the body

Layers of the Skin• Epidermis• very thin top layer of the skin• most epidermal cells are dead

• Dermis• lies beneath the epidermis• contains many other

small structures

• Subcutaneous Fat• bottom layer

Parts of the Skin• Hair follicle – where hair grows

• Sweat gland – releases sweat, which regulates the body and gets rid of waste

• Oil gland – releases oil, which keeps hair flexible and makes the skin waterproof

• Blood vessels – transport blood to the skin; regulate body temperature

Other Parts of the Skin• Hair & Nails• both grow from the base of a follicle or root• only living cells are at the base and push old cells up• provide protection and hair helps regulate body temperature

About the Skin• Melanin• chemical that determines color of the skin• a lot of melanin = darker skin• helps protect against UV radiation from the sun

• Skin Cancer• abnormal growth of skin cells• can develop from prolonged exposure to UV

radiation

Structure & MovementThe Musculoskeletal System

Kinds of Muscle• Smooth Muscle• found in the digestive tract and walls of blood vessels• involuntary (not under your control)

• Cardiac Muscle• found only in the heart• involuntary (not under your control)

• Skeletal Muscle• attached to your bones and allows you to move• can be involuntary or voluntary (you control the

movement)

Tendons• Tendons• connective tissue that attaches muscles to bones• when the muscle contracts, the bones are pulled up • Ex. contracting your bicep makes your arm move upward

Muscle Fatigue• Lactic Acid• chemical produced by muscle cells during respiration• if muscles are worked too hard too quickly lactic acid can

build up, this causes the muscles to burn or ache

Function of Skeletal System

• Protection• ex. ribs protect heart, skull protects brain

• Storage• store minerals and fat

• Movement• muscles pull on bones to make them move

• Blood cell formation• marrow inside the bones makes blood cells

Bone Structure

• Compact Bone• dense and rigid structure• no pores or open spaces• stores minerals (calcium and

phosphorus)

• Spongy Bone• many open spaces• provides strength and support

Bone Structure

• Cartilage• soft, flexible tissue usually replaced by bone• also found on the ends of bones to ease friction

and absorb shock

• Marrow• soft tissue inside bone• red marrow produces blood cells• yellow marrow is found in long bones

and stores fat

Joints- a place where two or more bones meet - held together by ligaments- connective tissue

that connects bone to bone.

• Three kinds of joints:• Gliding Joint

- bones gliding over one another (ex. wrist, vertebrae)

• Ball-and-Socket Joint- allows movement in all directions (ex. shoulder, hip)

• Hinge Joint- allows for bending at right angles (ex. knees, elbows)

Skeletal System Injuries & Disorders

• Sprain• when a ligament is stretched too far or torn

• Osteoporosis• bones become less dense and weak due to age or

poor diet

• Arthritis• swelling or stiffening of the joints

Communication & ControlThe Nervous & Endocrine Systems

The Nervous System

• The nervous system acts as the body’s central command post.

• It detects , processes, and responds to information in the body

• Communication occurs using electrical impulses.

Neurons• The basic unit of the nervous system is the Neuron-

a specialized nerve cell that transfers messages in the form of electrical impulses.

• Three parts of a neuron:• cell body – normal cell structure

• dendrite – branch-like structures

used to receive impulses

• axon – long, tail-like structure

covered in a myelin sheath (fat)

used to send impulses

Information Collection & Delivery

• Sensory Neurons – gather information about what is happening in and around the body

• Motor Neurons – send impulses from the central nervous system to other systems of the body

• Nerve – collection of axons bundled together with blood vessels and connective tissue

Peripheral Nervous System (PNS)• Peripheral Nervous System (PNS)• all of the parts of the nervous system except the brain and

spinal cord• uses specialized structures call nerves to carry information

between parts of the body

Central Nervous System (CNS)

• Central Nervous System (CNS)• receives messages from the

peripheral nervous system and responds by sending messages to the motor neurons

• made up of the brain and spinal cord

The Brain• Main control center of the nervous system• Three main parts of the brain:

• Cerebrum

• Cerebellum

• Medulla

Parts of the Brain

Cerebrum

• largest part of the brain

• where you think and carry most memories

• location of all your senses

• divided into two hemispheres• right side controls left side of

the body, and vice versa

Parts of the Brain

Cerebellum

• second-largest part of the brain

• located beneath the back of the cerebrum

• processes sensory information from muscles and joints (i.e. balance)

Parts of the Brain

Medulla

• part of the brain that connects to the spinal cord

• controls involuntary things like breathing, heart rate, blood pressure, and body temperature

Spinal Cord

• made of bundles of neurons that pass impulses to and from the brain

• surrounded by the vertebrae (protective bones of the spine)

• sensory neurons spinal cord brain spinal cord motor neurons

The Endocrine Systempituitary, thyroid, gonads

Function

• a collection of glands that secrete hormones into the body that regulate growth, development, and homeostasis

Hormones• chemical messengers released by an endocrine gland and

carried through the blood to different parts of the body• ex. adrenaline - released when you are scared, angry, or

excited to increase your heart rate and breathing

Endocrine Glands

• Pituitary gland• “master gland” that controls other

endocrine glands• located in the brain• makes human growth hormone (HGH)

• Thyroid gland• controls how you use energy

(metabolism)• in the neck

• Parathyroid gland• regulates calcium levels in the blood• behind the thyroid gland

Endocrine Glands

• Thymus gland• regulates the immune system to

help fight disease• behind the heart

• Adrenal glands• produces adrenalin to help the

body respond to danger• sit atop the kidneys

• Pancreas• regulates blood sugar levels by

secreting insulin

Endocrine Glands

• Ovaries (female)• produce estrogen to aid in

female reproduction• released during puberty

• Testes (male)• produce testosterone to aid

in male reproduction• released during puberty

Diseases & Disorders

• Diabetes• the pancreas does not make insulin properly so the body

cannot regulate blood sugar levels• patients must take insulin injections

• Hormone Imbalances• Thyroid – controls metabolism, so this can lead to obesity• Pituitary – controls growth, so this can lead to stunted

growth or being abnormally tall

The Respiratory Systemlungs, bronchi, diaphragm

Respiration

• The exchange of oxygen and carbon dioxide between living cells and their environment

• Includes breathing and cellular respiration

• The respiratory system is a group of organs that take in oxygen and release carbon dioxide

Upper Respiratory System

• Nose• air enters and exits through the nose• hairs and mucus in the nose trap dirt and particles

• Pharynx (Throat)• splits into two tubes – the esophagus (leads to the stomach) and

the trachea (leads to the lungs)• a tiny flap called the epiglottis covers the trachea to prevent

food from going into the lungs when swallowed

• Larynx• location of the vocal cords – two muscles stretched over the

trachea that vibrate when air passes through them

Lower Respiratory System

• Trachea• also known as the windpipe

• Bronchus• the trachea splits into two separate bronchi, one

going to each lung• the bronchi split further into smaller tubes called

bronchioles

• Alveoli• tiny air sacs located at the ends of each

bronchiole• Covered in blood vessels so gas exchange

can take place

Breathing

• the diaphragm is a dome-shaped muscle underneath your lungs• when it pushes downward you inhale, when it pushes

upward you exhale• spasm of the diaphragm gives you

hiccups

Respiratory Disorders

• Asthma• swelling and narrowing on the bronchioles• makes breathing more difficult

• Emphysema• damage to the alveoli• trouble getting oxygen to the body

• Lung cancer• can be caused by smoking

The Circulatory Systemheart, blood, arteries & veins

Functions

• moves blood throughout the body

• carries nutrients to your cells

• removes waste from your cells

• carries chemicals through your body

• regulates body temperature

Heart

• Made of cardiac muscle

• Right side of the heart pumps oxygen-poor blood to the lungs

• Left side pumps oxygen-rich blood to the body

Four chambers separated by valves:Upper = atriums (right and left)Lower = ventricles (right and left)

Path of Blood

Blood Vessels

• Three types of blood vessels:• Artery• Carries blood AWAY from the heart

• Vein• Carries blood TO the heart

• Capillary• Tiny blood vessels that allow for gas and waste exchange

between the blood and cells

Circulation

• Two types of circulation• Pulmonary Circulation –

between the heart and lungs• Pulmonary artery – carries blood

from heart to lungs• Pulmonary vein – carries blood

from lungs to heart

• Systemic Circulation – between the heart and body• Aorta – carries blood from heart

to body• Superior/Inferior Vena Cava –

carries blood from body to heart

Diseases & Disorders of the Circulatory System

• Atherosclerosis• build up of cholesterol in blood vessels• clogs pathways and blood flow becomes

blocked

• Heart Attacks• arteries going to the heart itself

become blocked• heart muscle cells die

Blood

• Fluid that carries nutrients, waste, and gases throughout the body

• Made up of four parts: • plasma• red blood cells• platelets• white blood cells

Parts of the Blood

Plasma• Fluid part of the blood

• A mixture of water, minerals, nutrients, sugars, proteins, and other substances

• All other parts of the blood are found within plasma

Red Blood Cells• Most of what blood is

made of

• Hemoglobin in your red blood cells helps carry oxygen to your body.

Parts of the Blood

Platelets• Pieces of larger cells

floating among blood cells

• Release chemicals that form a net at damaged vessel to stop blood flow and clot

White Blood Cells• Destroy pathogens (bacteria

and viruses) that attack your body

• Some release antibodies which identify and destroy pathogens

Blood Types

• Refers to the types of chemicals (antigens) you have on the surface of your red blood cells

• Type A = A antigens• Type B = B antigens• Type AB = both antigens• Type O = neither antigen

Can Receive From

Can Donate To

A A, O A, AB

B B, O B, AB

AB All types AB only

O O only All types

Universal Receptor = Type ABUniversal Donor = Type O

The Digestive Systemstomach, liver, intestines

Function

• organs that break down food to be used by the body

• Mechanical Digestion – breaking, crushing, mashing of food particles

• Chemical Digestion – large molecules are broken down into specific nutrients

Digestion in the Mouth

Teeth• chew and mash food

beginning mechanical digestion

• hardest substances in the body

Saliva• liquid made in the salivary

glands of the mouth• contain enzymes that begins

the chemical digestion of food

Esophagus

• long, straight tube connecting the throat and stomach

• squeezes food down to the stomach using muscle contractions called peristalsis

The Stomach

• muscular, saclike organ where food continues to get broken down mechanically and chemically

• releases small amount of enzymes and acid to break down food

• slowly releases the soupy mixture, now called chyme, into the small intestine

Pancreas

• located between the stomach and small intestine• released enzymes into the small intestine to continues digestion• also releases hormones to regular blood sugar levels

Helper Organs

Liver• located beside and above

the stomach on the right side

• produces bile to help break down fats

• also breaks down toxins

Gallbladder• small, green, saclike organ

located behind the liver

• stores the bile

Small & Large Intestine

• Small Intestine• muscular tube that is about 6 meters long• inside is covered in small projections

called villi where nutrients are absorbed

• Large Intestine (Colon)• stores and compacts undigested material

by absorbing water• feces (poop) are stored in the rectum and

eliminated through the anus

What to Know

• Mouth• Esophagus• Stomach• Pancreas• Liver• Gallbladder• Small Intestine• Large Intestine• Rectum

Nutrition

• Essential needs for human development:• Carbohydrates – give energy• Examples: fruits, vegetables, grains

• Proteins – build muscle• Examples: meat, dairy, beans

• Fats – protect body• Examples: oils, nuts, lard

• Vitamins & Minerals• Examples: zinc, calcium, potassium, vitamin A, vitamin C

Calories

• calories = how much energy is contained in food

• determined by using a calorimeter – food is burned to see how much heat (energy) is released

The Excretory Systemkidneys, urinary bladder

Function

• removal of waste materials from the body

• Parts of the Excretory System:• skin – sweating• lungs – exhaling• kidneys – urine

Kidneys

• a pair of organs that constantly clean the blood

• inside each kidney are about one million nephrons• Nephrons - microscopic filters

that remove harmful substances from the blood, including urea

• Urea - a nitrogen-based substance that is formed when cells use protein for energy

How Kidneys Work

• renal artery brings blood into each kidney

• tiny blood vessels bring blood to the nephrons

• blood gets filtered

• cleaned blood exits kidneys through a renal vein

• waste material leaves nephrons as urine

Exiting the Body

• urine leaves the kidneys through tubes called ureters

• ureters lead to the urinary bladder where urine is stored

• it will eventually leave the body through a tube called the urethra

Kidney Diseases & Disorders

• Urinary Tract Infection (UTI)• bacteria gets into the urinary tract (urethra, bladder, ureters)

and cause pain

• Kidney disease• damage to nephrons prohibits normal filtering of the blood• a machine must be used to filter the blood, called a dialysis

machine

Kidney Stones

• salts and other waste build up in the kidneys and make a hard stone-like substance that interferes with urination

• can be passed naturally or must be removed surgically

The Immune Systemdisease, T & B cells, antibodies

Disease

Noninfectious

• cannot be spread from one individual to another

• can be caused by genetics, habits (ex. smoking), poor diet• ex. cancer, heart disease

Infectious• can be spread from one

individual to another

• caused by pathogens (virus or organism that causes disease)

• some organisms that cause disease: bacteria, fungi, protists, worms

Pathogen Pathways

• Ways Pathogens Get Transferred:• Air• Contaminated objects (ex. doorknobs, keyboards)• Person to person• Animals (ex. dogs, ticks)• Food and water (ex. meat)

BELLWORK

• List some ways pathogens can be spread from one individual to another.

Viruses• Microscopic

• can be spread from one individual to another

• need the cells of living things to reproduce, therefore are not considered a living thing themselves

• Are treated with Vaccines.

Bacteria

• Some bacteria are pathogens

• Some bacteria that normally live in the body cause illness only when the person's immune system is weakened.

• They can enter the body through a cut, in the air, or on food. After they are in the body, they reproduce and cause disease.

• Some can:• make people sick by damaging tissue.• cause illness by releasing toxins.

• Antibiotics are medicines that stop the growth and reproduction of bacteria

The Immune System• Function• cells and tissues that recognize and attack foreign

substances in the body

• Parts of the Immune System• Macrophages• T-cells• B-cells

Responding to a Virus

• If pathogens get past your first line of defenses (skin, oil, mucus) your body will respond to destroy them.

• Macrophage• engulf and destroy the virus• engulf and destroy cells infected by the virus• display viral antigens (substances that stimulate

an immune response)

• Helper T-Cells• recognize the viral antigen and begin two responses:• T-Cell Response• B-Cell Response

Immune Responses

T-Cell Response

• activation of killer T-cells• recognize antigens on

infected body cells • kills the cells so they

cannot replicate

B-Cell Response

• activation of B-cells• b-cells divide and create

anitbodies (proteins that attach to specific antigens)

• antibodies cause viruses to clump together and become marked for destruction

Memory B-Cells

• normal B-cells create antibodies against a pathogen within two weeks

• some B-cells become memory B-cells, which means the next time your body encounters that pathogen your B-cells “remember” how to create the antibodies for it and you will be protected within 3 or 4 days

Challenging the Immune System

• Allergy• an overreaction to a harmless or common substance by the

immune system

• Autoimmune Diseases• diseases in which the immune system

mistakes body cells for pathogens and attacks them• ex. rheumatoid arthritis, multiple sclerosis, lupus

HIV/AIDS

• Human Immunodeficiency Virus (HIV)• causes acquired immune deficiency syndrome (AIDS)

• infects the cells of the immune system, specifically the helper T-cells, and destroys them

• killer T-cells and B-cells do not get activated, therefore the body cannot defend itself against the virus or any other pathogens

• Most people die from other diseases that their body could not fend off

The Reproductive Systemovaries, testes, egg, sperm

Male Reproductive System

• Testes – sperm is produced here

• Epididymis – sperm is stored here

• Vas Deferens – sperm leave the testes through these tubes

• Prostate Gland – other fluids are added here to make semen

• Urethra – semen leaves the body through this tube out the penis

Female Reproductive System

• Ovaries – eggs are produced here

• Fallopian Tubes – eggs travel down these to get to the uterus

• Uterus – fertilized eggs attach here and this is where the fetus develops

Menstruation

• beginning at puberty eggs are released from the ovary once a month to be fertilized

• the uterus begins to prepare for pregnancy by building up blood vessels in the uterine walls

• if the egg does not become fertilized the uterus will release the egg along with the all the uterine lining through the vagina

Fertilization

• An egg becomes fertilized when a sperm enters the egg cell. The fertilized egg is now called a zygote.

• The zygote begins to divide into many cells and implants itself into the uterine wall. It is now called an embryo.

Pregnancy

• The placenta gives the embryo nutrients and picks up any waste products.

• It is attached to the placenta by the umbilical cord.

• The embryo develops inside a sac called the amnion which is filled with amniotic fluid.