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.