Homeostasis and an Introduction to Body System

Homeostasis

ability of a system to maintain a steady internal state

Negative feedback

stimulus and response are opposite

Positive feedback

stimulus and response are the same

homeostasis

maintains stable internal conditions, keeps body variables within a normal range, regulates substances such as blood glucose, uses hormones to adjust levels
Ex: high glucose → insulin release → glucose lowered
low glucose → glucagon released → glucose raised

insulin

hormone that LOWERS blood glucose

glucagon

hormone that raises blood glucose

feedback mechanism

system that regulates a variable using stimulus and response

integumentary system

protects body and regulates temperature, produces vitamin D, waste secretion, sensation
includes: hair, skin, nails, sweat glands, sebaceous glands

skeletal system

supports body and produces blood cells, mineral storage
includes: bones, ligaments, cartilage

muscular system

produces movement and heat
includes: skeletal muscle, smooth muscle, cardiac muscle

nervous system

receives sensory information, detects changes and stimulates muscles and glands
includes: brain, spinal cold, & receptors

endocrine system

regulates body using hormones
includes: pituitary gland, thyroid gland, adrenal gland, pancreas, ovaries, testies

lymphatic system

returns fluid to blood and defends against infection, transports absorbed nutrients
includes: lymph vessels, lymph nodes,

blood system

transports gases, nutrients, waste, hormones, electrolytes
includes: plasma red blood cells, white blood cells, platelets

cardiovascular system

transports blood throughout the body
includes: heart, arteries, capillaries, veins

digestive system

breaks down and absorbs food, eliminates solid waste
includes: mouth, tongue, teeth, salivary glands, pharynx, esophagus, liver, gallbladder, pancreas, intestines

respiratory system

supplies oxygen and removes carbon dioxide
includes: nasal cavity, pharynx, larynx, trachea, bronchi, lungs

urinary system

removes waste and maintains fluid balance
includes: kidneys & ureters, urinary bladder, urethra

reproductive system

produces hormones and enables reproduction
includes: mammary glands, ovaries, uterus, epididymis, testes, vagina, penis, prostate

immune system

protects against pathogens
includes: white blood cells, antibodies, thymus, spleen