homeostasis and feedback control

physiology

study and scientific investigation of the processes and function of living things; goal = understand homeostasis even with a changing surrounding environment and be able to predict the body’s responses

subdisciplines of physiology

pathophysiology- abnormal conditions and the structural and functional changes that occur from diseases

exercise physiology- changes in structure and function from exercise

cell physiology- processes in cells

systemics physiology- functions of organ systems

body levels of organization

1) chemical- interaction between atoms that form molecules

2) cellular- smallest living unit

3) tissue- groups of similar cells and surrounding materials

4) organ- one or more tissues function together

5) organ system- groups of organs that function together

6) organism- any living thing

integumentary system

provides protection, regulates temperatures, prevents water loss, helps produce vitamin D; consists of skin, hair, nails, and sweat glands

skeletal system

protection, support, movement, produces blood cells, stores minerals and fat; consists of bones, associated cartilages, ligaments, and joints

muscular system

produces movement, maintains posture, produces body heat

lymphatic system

removes foreign substances from blood and lymph, combats disease, maintains fluid balance; consists of lymphatic vessels, lymph nodes, and other organs

respiratory system

exchanges O2 and CO2 between blood and air and regulates blood pH; consists of lungs and respiratory passages

digestive system

performs mechanical and chemical processes of digestion, absorption of nutrients, elimination of waste; consists of mouth, esophagus, stomach, intestines, and accessory organs

nervous system

detects sensations, controls movements and physiological functions; consists of brain, spinal cord, nerves, and sensory receptors

endocrine system

influences metabolism, growth, reproduction; consists of glands that secrete hormones

cardiovascular system

transports nutrients, waste products, gases, and hormones, plays a role in immune response and temperature regulation; consists of heart, blood vessels, and blood

urinary system

removes waste products from blood and regulates blood pH, ion and water balance; consists of kidneys, urinary bladder, and ducts that carry urine

female reproductive system

produces oocytes, site of fertilization and fetal development, produces milk and hormones; consists of ovaries, vagina, uterus, mammary glands, and associated structures

male reproductive system

produces and transfers sperm cells to female and produces hormones; consists of testes, accessory structures, ducts and penis

homeostasis

maintenance of relative constant conditions in the internal environment of the blody

negative feedback mechanism

regulates most systems in the body by resisting or counteracting a deviation from the set point; if a variable increases, the system responds to decrease it

components of negative feedback mechanism

receptor- monitors value of variable

control center- establishes set point

effector- can change value of varaible

positive feedback mechanism

a response to the original stimulus results in deviation becoming even greater (unusual in most healthy physiological systems)