Unit 7/8 Flashcards
homeostasis
Process by which a constant internal environment is maintained despite changes in the external environment.
dynamic equilibrium
condition that refralns stable within fluctuating limits
negative feedback
process by which a mechanism is activated to restore conditions to their original state
positive feedback
process by which a small effect is amplified
thermoregulation
maintenance of body temperature within a range that enables cells to function efficiently
hypothalamus
region of the vertebrate’s brain responsible for coordinating many nerve and hormone functions
deamination
removal of an amino group from an organic compound
urea
nitrogen waste formed from two molecules of ammonia and one molecule of carbon dioxide
uric acid
waste product formed from the breakdown of nucleic acids
contractile vacuole
a structure in unicellular organisms that maintains osmotic equilibrium by pumping fluid out from the cell
ureters
tubes that conduct urine from the kidneys to the bladder
urethra
tube that carries urine from the bladder to the exterior of the body
cortex
outer layer of the kidney
medulla
area inside of the cortex
renal pelvis
area where the kidney joins the ureter
nephrons
functional units of the kidneys
afferent arterioles
small branches that carry blood to the glomerulus
glomerulus
high-pressure capillary bed that is the site of filtration
efferent arterioles
small branches that carry blood away from the glomerulus to a capillary net
peritubular capillaries
network of small blood vessels that surround the nephron
Bowman’s capsule
cuplike structure that surrounds the glomerulus
proximal tubule
section of the nephron joining the Bowman’s capsule with the loop of Henle
loop of Henle
carries filtrate from the proximal tubule to the distal tubule
distal tubule
conducts urine from the loop of Henle to the collecting duct
collecting duct
tube that carries urine from nephrons to the pelvis of a kidney
filtration
process by which blood or body fluids pass through a selectively permeable membrane
reabsorption
transfer of glomerular filtrate from the nephron back into the capillaries
secretion
movement of materials, such as ammonia and some drugs, from the blood back into the distal tubule
threshold level
maximum amount of material that can be moved across the nephron
interstitial fluid
fluid that surrounds the body cells
antidiuretic hormone (ADH)
causes the kidneys to increase water reabsorption
osmoreceptors
specialized nerve cells in the hypothalamus that detect changes in the osmotic pressure of the blood and surrounding extracel-lular fluids (ECF)
aldosterone
hormone that increases Na+ reabsorption from the distal tubule and collecting duct
hormones
chemicals released by cells that affect cells in other parts of the body
endocrine hormones
chemicals secreted by endocrine glands directly into the blood
growth hormone (GH)
hormone, produced by the pituitary gland, that stimulates growth of the body; also known as somatotropin (STH)
insulin
hormone produced by the islets of Langerhans in the pancreas; insulin is secreted when blood sugar levels are high
epinephrine
hormone, produced in the adrenal medulla, that accelerates heart rate and body reactions during a crisis (the fight-or-flight response);
also known as adrenaline
steroid hormones
group of hormones, made from cholesterol, that includes male and female sex hormones and cortisol
cortisol
hormone that stimulates the conversion of amino acids to glucose by the liver
protein hormones
group of hormones, composed of chains of amino acids, that includes insulin and growth hormone
cyclic adenosine monophos-phate (cyclic AMP)
secondary chemical messenger that directs the synthesis of protein by ribosomes
thyroxine
iodine-containing hormone, produced by the thyroid gland, that increases the rate of body metabolism and regulates growth
pituitary gland
gland at the base of the brain that, together with the hypothalamus, functions as a control centre, coordinating the endocrine and nervous systems
glucagon
hormone produced by the pancreas; when blood sugar levels are low, glucagon promotes conversion of glycogen to glucose
diabetes
chronic disease that occurs when the body cannot produce any insulin or enough insulin, or is unable to use properly the insulin it does make
adrenal medulla
found at the core of the adrenal gland, the adrenal medulla produces epinephrine and norepinephrine
norepinephrine
also known as noradrenaline, it initiates the fight-or-flight response by increasing heart rate and blood sugar
adrenal cortex
outer region of the adrenal gland that produces glucocorticoids and mineralocorticoids
glucocorticoids
various hor-mones, produced by the adrenal cortex, designed to help the body meet the demands of stress
mineralocorticoids
hormones of the adrenal cortex important for regulation of salt-water balance
thyroid gland
a two-lobed gland at the base of the neck that regulates metabolic processes
parathyroid glands
four pea-sized glands in the thyroid gland that produce parathyroid hormone to regulate blood calcium and phosphate levels
thyroid gland
a two-lobed gland at the base of the neck that regulates metabolic processes
parathyroid glands
four pea-sized glands in the thyroid gland that produce parathyroid hormone to regulate blood calcium and phosphate levels
calcitonin
hormone produced by the thyroid gland that lowers calcium levels in the blood
goiter
disorder that causes an enlargement of the thyroid gland
parathyroid hormone (PTH)
hormone produced by the parathyroid glands, which will increase calcium levels in the blood and lower the levels of phosphates
prostaglandins
hormones that have a pronounced effect in a small localized area
anabolic steroids
substances that are designed to mimic many of the muscle-building traits of the sex hormone testosterone
testosterone
male sex hormone produced by the interstitial cells of
the testes
spermatogenesis
process by
which spermatogonia divide and differentiate into mature sperm cells
gonadotropic hormones
hormones produced by the pituitary gland that regulate the functions of the testes in males and the ovaries in females
follicle-stimulating hormone
(FSH)
in males, hormone that increases sperm production
luteinizing hormone (LHI)
in males, hormone that regulates the production of testosterone
gonadotropin-releasing hormone (GnH)
chemical messenger from the hypothalamus that stimulates secretions of FSH and LH from the pituitary
follicles
structures in the ovary that contain the egg and secrete estrogen
ovulation
release of the egg from the follicle held within the ovary
corpus luteum
a mass of follicle cells that forms within the ovary after ovulation; secretes estrogen and progesterone
flow phase
phase of the menstrual cycle marked by shedding of the endometrium
follicular phase
phase marked by development of ovarian follicles before ovulation
estrogen
female sex hormone that activates the development of female secondary sex characteristics, including development of the breasts and body hair, and increased thickening of the endometrium
luteal phase
phase of the menstrual cycle characterized by the formation of the corpus luteum following ovulation
progesterone
female sex hormone produced by the ovaries that maintains uterine lining during pregnancy
follicle-stimulating hormone
(FSH)
in females, a gonadotropin that promotes the development of the follicles in the ovary
luteinizing hormone (LH)
in females, a gonadotropin that promotes ovulation and the formation of the corpus luteum
