Human Anatomy and Body Systems

Levels of Organization

Remember, the human body is organized in several levels, from the simplest to the most complex. . .

Cells – the basic unit of life

Tissues – clusters of cells performing a similar function

Organs – made of tissues that perform one specific function

Organ Systems – groups of organs that perform a specific purpose in the human body

***The purpose of the 11 organ systems is for the human body to maintain homeostasis.

The 11 Human Body SystemsThe 11 human body systems are as follows:

-- nervous system -- integumentary system

-- respiratory system -- digestive system

-- excretory system -- skeletal system

-- muscular system -- circulatory system

-- endocrine system -- reproductive system

-- lymphatic (immune) system

The Digestive SystemFunction: to convert food particles into simple

molecules that can be absorbed into the blood and used by the body

Major Organs and their Functions:Mouth – to chew and grind up food (mechanical)

-- amylase in the saliva begins the chemical breakdown

Esophagus – pipe connecting mouth to stomach

Stomach – secretes pepsin, an enzyme that breaks down food.

The stomach has a pH of 2.

•Small Intestine – after digestion is complete, the chyme (processed stomach contents) enters the small intestine where it is absorbed into the bloodstream by the help of small hairs called villi.

•Large Intestine – removes water from the chyme and gets the waste ready for excretion

The nutrients that are absorbed during digestion travel into the Circulatory System to be distributed through the body!

Liver – produces bile, which breaks down fats in foods. This is an accessory organ.

Gallbladder – pouch-like organ that stores bile for future use

The Digestive System

Explain how the Digestive system works closely with the:

Circulatory systemMuscular systemEndocrine system

The Excretory System

Kidneys-Ureter-Bladder-Urethra

Function: to rid the body of wastes, including excess water and salts

Major Organs of excretion

Kidneys – the main organ of the excretory system; excretion begins here

-- Kidneys filter the blood, removing wastes

More excretory organs:•Skin – sweat glands remove excess water and salts from the body

•Lungs – expel the waste product carbon dioxide (cellular respiration)

•Question: Can one organ be part of TWO systems?

Explain how the excretory system works closely with the:

Circulatory systemIntegumentary systemHomeostasis

The Nervous System

Function: to coordinate the body’s response to changes in its internal and external environment

The basic unit of structure in the nervous system is the neuron (nerve cell)

Major Organs of the Central Nervous System

Brain – control center of the body

• Divided into 2 halves

• Controls conscious activities, intelligence, memory, language, muscle movement, senses

Brain stem controls breathing and heart rate

Medulla oblongata reacts to increased CO2 levels to increase rate of breathing

•Spinal Cord – sends instructions from the brain to the rest of the body and vice versa

-- any organism with a major nerve cord is classified as a chordate

•Nerves – conduct impulses to muscle cells throughout the body

Explain how the nervous system works closely with the:

Integumentary systemMuscular systemEndocrine system

Which 2 body systems are working together in this image?

The Circulatory SystemFunction: to deliver oxygen to the body and brain; to deliver nutrients from the digestive system.

Image of the Circulatory System

•Heart – the major muscle of the circulatory system

•pumps blood through its four chambers (two ventricles and two atria)

•pumps deoxygenated blood into the lungs, where it gets oxygenated, returns it to the heart, and then pumps out through the aorta to the rest of the body

•valves regulate the flow of blood between the chambers

Arteries – carry blood away from the heart and to the major organs of the body

Veins – carry blood back to the heart away from the major organs of the body

Capillaries – small blood vessels (one cell thick) where gas exchange occurs, connects arteries and veins

Red Blood Cells: contain hemoglobin; carries oxygen throughout body

White Blood Cells: fight disease

Platelets: fragments that help blood clot

Plasma: liquid part of the blood

Explain how the circulatory system works closely with the:

Respiratory systemDigestive systemEndocrine system

The Respiratory SystemFunction: to provide the body with a fresh supply of oxygen for cellular respiration and remove the waste product carbon dioxide

•Major Organs•Nose – internal entry and exit point for air

•Trachea – the “windpipe”•Bronchial Tubes – the two large passageways that lead from the trachea to your lungs (one for each lung)

•Alveoli – clusters of tiny sacs where gases are exchanged with the bloodstream.

Diaphragm - the muscle that causes you to breath

Cilia – tiny hairs that line the air passages that trap tiny particles

The respiratory system and circulatory system work closely together:

Explain how the respiratory system works closely with the:

Circulatory systemMuscular systemEndocrine system

The Muscular SystemFunction: works with the skeletal and nervous system to produce movement, also helps to circulate blood through the human body

Muscle contractions can be:Voluntary: skeletal musclesInvoluntary: smooth (intestinal)

muscles, cardiac muscle

Major Skeletal Muscles-- biceps (flexor) -- triceps (extend)-- deltoids -- rectus abdominus-- gluteus maximus -- hamstrings

•Over 600 muscles in your body•Control movement•Voluntary: you choose to move them

•Involuntary: controlled unconsciously by the brain

Which muscle would raise this arm? Straighten the arm?

Explain how the muscular system works closely with the:

Circulatory systemSkeletal systemNervous system

Integumentary System•Comprised of the largest organ in the

body which is our skin. Hair and nails are also in this system.

Functions:•Skin is our first line of defense against

disease. It also helps regulate body temperature, excretes wastes through sweating, and maintains homeostasis in a variety of ways.

Examples of human HOMEOSTASIS:

1. Sweating2. Shivering3. Thirst4. Increased/decreased breathing5. Increased/decreased heart rate

Integumentary

Explain how the integumentary system works closely with the:

Circulatory systemNervous systemExcretory system

The Skeletal SystemFunction: to provide structure and support to the human body

Bones are where new blood cells are generated (in the marrow), and require the mineral calcium for strengthMajor Bones of the Human Body-- femur (thigh bone) -- humerus (upper arm)

-- radius and ulna (lower arm) -- cranium (skull)

-- sternum (breastbone) -- clavicle (shoulder blade)

-- fibula and tibia (calf) -- vertebrae (back)

-- scalpula (shoulder) -- pelvic bone

•Axial Skeleton: (white)skull, ribs, spine

•Appendicular Skeleton: (purple) arms, legs, pelvis

•Bones are living tissue

•There are 206 bones in the human body

•The skeletal system works closely with the muscular system (the muscles move the bones)

Explain how the skeletal system works closely with the:

Respiratory systemMuscular systemEndocrine system

The Lymphatic (Immune) SystemFunction: to remove infectious diseases and other pathogens from the human body

The lymphatic system transports tissue fluid (called lymph) and filters out disease-causing pathogens (through lymph nodes)

•Major Organs•Skin –the body’s first line of defense•Tonsils – trap bacteria that enter mouth/nose

•Lymph Nodes – help restore fluid lost by the blood and return it to the circulatory system

•Spleen – filters out and destroys bacteria and worn out blood cells

•White Blood Cells – recognize pathogens and create antibodies to tag and remove these

•HIV attacks helper T cells (a type of white blood cell)

Explain how the lymphatic system works closely with the:

Circulatory systemIntegumentary systemSkeletal system

Reproductive SystemFunction: The reproductive system helps humans reproduce and ensures the survival of the species.

•The primary female reproductive organs are the ovaries, and the primary male reproductive organs are the testes.

•Ovaries produce the female hormones estrogen and progesterone and the testes produce testosterone.

•Through meiosis, the female (eggs) and male (sperm) gametes are produced. They have HALF the number of chromosomes as other cells (haploid).

•When an egg and sperm fuse, fertilization takes place and a zygote is formed. It develops into an embryo which becomes a baby.

•Sperm cells have flagella for movement

. Each month, an egg is released by one of the 2 ovaries. If fertilization occurs, it will occur in the oviduct.

The fertilized egg (zygote) travels to the uterus and implants into the uterine wall. The fetus will develop in the uterus for 9 months.

If a human body cell has 46 chromosomes, how many

chromosomes does each gamete have after meiosis?

Explain how the reproductive system works closely with the:

Endocrine systemMuscular systemNervous system

The Endocrine SystemFunction: to control growth, development, metabolism and reproduction through the production and secretion of hormones

Major Organs

Pancreas: secretes insulin which regulates blood sugar

Pituitary gland (brain): secretes growth hormone

Thyroid: regulates metabolism

Adrenal Glands: prepare body for fight or flight

Testes & Ovaries: produce sex hormones

Explain how the endocrine system works closely with the:

Circulatory systemNervous systemRespiratory system

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