terms to know chapter 16-21

homeostasis

a steady state of internal conditions that organisms must maintain in order to sustain life

stimuli

events that trigger specific functional responses

osmotic balance

solutes and water in body fluids

thermoregulation

an organism’s ability to maintain a suitable body temperature

endotherm

animals that maintain a constant body temperature even as environmental temperature changes

ectotherm

animals that do not have internal control of body temperature, but instead use behavioral thermoregulation

osmoregulation

removes waste from the body and maintains osmotic balance in body fluids, including blood plasma and interstitial fluid

blood plasma

plasma is the liquid portion of blood

interstitial fluid

the fluid found between cells in the body, similar in constitution to the fluid component of blood, but without the high concentrations of proteins

kidney tubules

tiny, long convoluted tubes within the nephrons of kidneys that process filtered blood

urination

removing liquid

heterotroph

organisms incapable of photosynthesis that must therefore obtain energy and carbon from food by consuming other organisms

digestion

breaking food particles into smaller components

absorption

moving substances across tissues and into cells

bolus

a mass of food resulting from chewing and mixing with saliva

alimentary canal

digestive tube

defacation

pooping

systemic circuit

blood circulates through the body carrying O₂ away from tissues and cells and waste products, including CO₂, away from tissues and cells

pulmonary circuit

blood circulates to the lungs for oxygenation and back to the heart to enter systemic circuit

valves

prevent the backward flow of blood

capillaries

vessels with walls that are 1-cell thick

ventilation

moving air into and out the lungs

respiration

exchange of O₂ and CO₂ between air sacs of lungs and blood

hormones

chemical messengers that are released into body fluids (often blood stream) and can act on target tissues that have specific receptors

axial skeleton

consists of the bones of the skill, ossicles of the middle ear, hyoid bone, vertebral column, and thoracic cage

appendicular skeleton

consists of the bones of the pectoral limbs, pectoral girdle, pelvic limb and pelvic girdle

intercalated disks

specialized junctions between cardiac muscle fibers (cardiomyocytes) that allow for rapid electric transmission, called an action potential, and nutrient exchange

muscle fiber

muscle cell, made up of hundreds and thousands of smaller myofibrils

myofibril

long cylindrical structures that lie parallel to the muscle fiber

sacromere

plasma membrane

neurons

functional cells

glial cells

support cells

dendrites

tree-like structures that extend away from the cell body to receive messages from other neurons at specialized junction

soma

neuron cell body

axon

a tube-like structure that propagates a signal from a neuron’s cell body to axon terminals