bio unit 6: human body

negative feedback

a change in one direction stimulates the control mechanism to counteract further change in the same direction

organ system

a group of organs that work together to perform a specific function

digestive system

aka the alimentary canal, takes in food, breaks it down into molecules small enough for the body to absorb, and gets rid of undigested molecules and waste

large intestine

aka the colon, contains any waste not used for energy production and is secreted

peripheral nervous system

all the stuff outside central nervous system, liaison between CNS and body (from brain to rest of body)

dendrites

antennae of the neuron that receives information from other cells

sacromere

area between two Z lines on a myofibril

hypothalamus

area of the brain that coordinates the activities of the nervous and endocrine systems

areteries

blood vessel that carries blood away from heart and has elastic fibers that allow them to expand

veins

blood vessel that carries blood back to the heart and contains waste material

capillaries

blood vessel that connects the arteries and veins, very small, but there are a lot of them, and they bring materials to cells

ostreocytes

bone cells that maintain healthy bone tissue

axial skeleton

bones of skull, spine, ribs, and sternum

flexor tendon

causes joint to bend

extensor tendon

causes joint to straighten

oxytocin

causes uterus to contract during birth, mammary glands to produce milk, associated with love

hormones

chemical signals secreted by the endocrine glands that act to regulate the activity of other cells in the body

alveoli

cluster of air sacs which are located at the end of bronchioles (smaller things off bronchi)

lymphatic system

collects and recycles fluids leaked from cardiovascular system

lymph nodes

concentrated in armpits, neck, and groin, contain lymphocytes (white blood cells), and filter substances from lymphatic fluid

circulatory system

connects muscles and organs through vessels and pumps blood

nervous tissue

consists of nerve cells and their supporting cells, carry info throughout the body

small intestine

consists of the duodenum, jejunum, and ileum that breaks down food using enzymes from pancreas, liver, and gall bladder

central nervous system

control center of the body; interprets and responds to info from environment and from within body

somatic nervous system

controls muscles and voluntary movement

autonomic nervous system

controls organs and glands; involuntary

tendons

dense connective tissue that attaches skeletal muscles to bones

compact bone

dense connective tissue, outer layer of bone

endocrine glands

ductless organs that secrete hormones into bloodstream or extracellular fluid

muscle tissue

enables the movement of body structures

axon terminal

ends of axon that communicates with other cells

salivary amylase

enzyme in saliva that breaks down carbohydrates

lipase

enzyme that breaks down lipids

pepsin

enzyme that is a part of gastric juices that begins protein digestion

red blood cells

erythrocytes, cells that carry oxygen

epiglottis

flap of tissue that covers opening of larynx to prevent food from going to the lungs

plasma

fluid that makes up 60% of blood, 90% water and 10% solutes (like metabolites, wastes, salts, proteins)

dermis

functional layer of skin underneath epidermis that has nerve cells, blood vessels, hair follicles, and specialized skin cells

sweat glands

help remove excess body heat through water

brain stem

helps with homeostasis by regulating heart beat, breathing, body temp, and sleep

steroid hormones

hormones made of lipids that are fat soluble

villi

inner lining of jejunum and ileum that increases surface area to absorb more nutrients

cerebrum

largest part of the brain responsible for learning, memory, perception, and intellectual function

rectum

last part of the colon where peristalsis moves solids through, solids are ejected through anus

myelin sheath

layer of insulation on axon that helps nerve impulses move faster down the axon

white blood cells

leukocytes, defends the body against pathogens

epithelial tissue

lines most body surfaces, and it protects other tissues from dehydration and physical damage

trachea

long, straight tube in chest cavity

spongy bone

loosely structured network of separated connective tissue

androgen

male sex hormone, testosterone

axon

membrane-covered extension of cytoplasm that conducts nerve impulses

pharynx

muscular tube in upper throat that serves as a passageway for air and food

action potential

nerve impulse; local reversal of polarity (negative to positive)

stomach

organ that mechanically breaks down food and chemically breaks down proteins

gland

organ whose function is to secrete materials into other regions of the body

epidermis

outermost layer of skin made of epithelial cells

pancreas

performs both endocrine and exocrine functions for digestion and blood glucose regulation

melanin

pigment produced by cells of the inner layer of the epidermis

synapse

place where a neuron meets another cell but do not touch

platelets

play an important role in the clotting of blood, stack up against scrapes to prevent blood loss and for new skin to reform over

diaphragm

powerful muscle spanning rib cage under lungs and aids in respiration

keratin

protein that makes skin tough and waterproof

cerebellum

regulates balance, posture, and involuntary movement

ADH (antidiuretic hormone)

regulates how much water the kidneys keep or dispose of (osmoregulation)

positive feedback

regulation where high levels of a hormone stimulate the output of even more hormones

adrenal cortex

responds to long term stress from endocrine signal (ACTH from pituitary) by secreting corticosteroids

adrenal medulla

responds to short term stress from nervous system by secreting epinephrine (adrenaline) and norepinephrine (noradrenaline)

glucagon

secreted by pancreas alpha cells, causes liver cells to break down glycogen into glucose to raise blood glucose back to homeostasis

insulin

secreted by pancreas beta cells, causes body cells to take in glucose from blood, and the liver stores excess glucose as glycogen

appendicular skeleton

shoulders, hips, arms, and legs

neurotransmitter

signal molecules triggered by the impulse, way of sending info

subcutaneous tissue

skin layer underneath dermis made of connective tissue that is mostly fat that acts as shock absorber, stores energy, and conserves body heat

myofibril

small cylindrical structures found inside muscle fibers

bronchi

smaller tubes off trachea that lead to lungs

bone marrow

soft tissue that fills cavities in spongy bone

target cells

specific cell that a hormone binds to and acts on that have specific protein receptors

progestin

steroid hormone that maintains pregnancy and prevents further ovulation during pregnancy, progesterone

estrogen

steroid hormone that promotes development and maintenance of female characteristics of the body

ligaments

strong bonds of connective tissue that hold together the bones of a joint

connective tissue

support, protect, and insulate the body

homeostasis

the relatively consistent internal, physical, and chemical conditions that organisms maintain

myosin

thick protein filaments

actin

thin protein filaments

synaptic cleft

tiny gap between axon terminal and receiving cell

hypothyroidism

too few thyroid hormones are releases, causes weight gain, tiredness, intolerance to cold

hyperthyroidism

too many thyroid hormones are released, causes raised body temp, profuse system, irritability, increased blood pressure

periosteum

tough exterior membrane surrounding bone, made of blood vessels that supply nutrients to bones

esophagus

tube that connects the mouth to the stomach

larynx

voice box, located in upper neck, plays a part in swallowing, breathing, and phonotation

joints

where two bones meet, pads of cartilage cushion the ends of the bones of a joint