Ch.13 section 1Organ systems and Homeostasis

Our body Each part of the body has a specific

function, or job. The levels of organization in the human

body consists of:› Cells› Tissues› Organs› Organ systems

Cells Cell theory: a cell is the basic unit of

structure and function of a living thing Structure:

› Membrane› Cytoplasm› Nucleus

Functions: cellular respiration, grow, reproduce, excrete waste

Tissues Muscles tissue

› Can contract (shorten) to move the body Nervous tissue

› Directs and controls› Carries electrical messages

Connective tissue› Provides support and connects: › bone and fat

Epithelial tissue› Skin› lining of digestive system

Organs and Organ Systems 11 organ systems:

› Integumentary› Skeletal› Muscular› Circulatory› Respiratory› Digestive› Excretory› Immune› Reproductive› Nervous› Endocrine

Integumentary system Skin, hair, and nails

make up your body’s covering

Create a barrier Regulate your body

temp Remove waste –

perspire Works with nervous

system to give info about your environm.

Skeletal Bones and other

connective tissues Supports the body

and gives it structure

Protects body’s organs

Produce bloods cells Connective tissues

attaches bones together

Muscular Move the body by

pulling on the skeleton

Involuntary muscles work by themselves

Muscles and bones: musculoskeletal system

Cells – fibers – muscle groups

Circulatory Transportation network –

carries food and oxygen Collects waste Transports blood Powered by pumping of

blood: heart Away: arteries To: veins Capillaries: smallest –

connect the arteries and veins- reach every cell

Respiratory Lungs : takes in

oxygen and disposes of carbon dioxide

Air moves into the lung then to the capillaries

Oxygen crosses into the blood

Lung expands due to the actions diaphragm.

Digestive Digestion:

breakdown of food into small molecules the body can use

Liver produces bile and pancreas makes enzymes which help break down the food

Water is removed in large intestine

Excretory Body makes excess

water and waste Excretory system

removes these waste products

Kidneys has nephrons which filters blood

Urine flows from kidney to urinary bladder

Immune Protects the body from

disease-causing bacteria and viruses(pathogens)

White blood cells attack and destroy viruses or make antibodies (proteins)

The immune system remembers the past pathogens and destroys them quicker the next time. (immunity)

reproductive Organs that

produce sex cells Sex cells carry DNA

– information Organs can also

produce chemicals that regulate the physical development

Nervous Takes info from envir

and body – processes this info and commands the body to respond

Some times, you control the brain, in other times, the brain decides for you (involuntary)

Brain + spinal cord + nerve cells

Endocrine Helps regulate the

activities of the organs by releasing hormones (chemicals that change the activity in cells)

Collection of glands (tissues that produce and release hormones)

Brain signals how much hormones to produce

Homeostasis (hoh-mee-oh-stay-sis)

Process by which an organism’s internal environment is kept stable in spite of changes in the external environment

Warm blooded… 37 °C – even when it’s cold or hot

Sweating… or shivering Stress : reaction of your body to potentially

threatening, challenging, or disturbing events.- body produces adrenaline to carry more oxygen to body cells.