lab 15 Flashcards
function of the kidneys
- Excretion and the maintenance of a constant internal environment.
- Eliminates nitrogenous waste (urine), water, and salt. -Conserves necessary substance such as protein and glucose.
urinary bladder
temporary storage of urine
3 layers that surround the kidney
1-renal capsule
2-middle adipose capsule
3-renal fascia
-these 3 layers help protect the kidney from trauma and anchor it firmly in place.
nephron
- tubular structures that perform all phases of of urine formation(glomerular filtration, tubular reabsorption, tubular secretion).
- consists of a renal corpuscle and a renal tubule
- 2 types: cortical and juxtamedullary
collecting duct
receives urine from many nephrons
route of urine from glomerulus –> urethra
Glomerulus-> Bowman’s capsule-> Proximal convoluted tubule-> descending limb->loop of Henle -> ascending limb -> distal convoluted tubule -> collecting duct -> renal pyramid -> renal papilla -> minor calyx -> major calyx -> renal pelvis -> ureter -> urinary bladder -> urethra.
glomerulus
where filtrate is first formed
glomerular filtration
The passive process in which materials are separated based on their size in relation to the pores of the filtration membrane. They are forced through the membrane by glomerular hyrdrostatic pressure (sort of like glomerular blood pressure). E.g. water can pass through the filtration membrane, but blood cells are retained in blood.
tubular reabsorption
process which substances the body needs, such as glucose and water, reenter the blood from the filtrate. Begins in proximal convoluted tubule.
tubular secretion
process by which substances enter the filtrate from the blood in the peritubular capillaries. Allows waste and other materials, that were not passed into the filtrate during glomerular filtration, to leave the body in the urine.
pH of blood
must maintain a constant level of about 7.4 at all times
Antidiuretic hormone (ADH)
- helps prevent wide swing in water balance to prevent dehydration or water overload.
- i.e. Add water (dilute) ADH production decreases and you pee a lot. Salty blood (dehydration) increases ADH production and stimulates kidneys to reabsorb water.
- produced by hypothalamus, secreted by posterior pituitary gland
Diabetes insipidus
- a condition in which ADH secretion is deficient, and large amounts of urine are produced accompanied by extreme thirst.
- produced by adrenal gland cortex
Aldosterone
Helps maintain the sodium and potassium concentration of ECF by stimulating re-absorption of sodium ions and water, and promoted potassium excretion.
normal pH range of Urine
4.8 (a diet high in protein and whole wheat) - 7.5 (a vegetarian diet)
specific gravity
- the relative amounts of solutes (particles) to solvent in a solution.
- water SG= 1.0
- usual SG 1.005-1.030 (higher the #, the greater density of the urine)
presence of glucose in urine
may indicate diabetes mellitus
presence of protein in urine
may indicate glomerulonephritis or severe hypertension, pregnancy, vigorous exercise or high protein intake.
presence of blood in urine
may indicate glomerular infection, physical trauma to kidney tissue, TB, tumors of the urinary tract, kidney stones, or severe burns.
presence of ketones in urine
starvation or untreated diabetes mellitus
diuresis
increased or excess production of urine
hormones
chemical messengers that are secreted by endocrine glands into the blood stream, and regulate the metabolic functions of other cells in the body.
target tissue
tissue specifically influenced by a particular hormone.
pituitary gland
- controls or influences most of the other endocrine glands.
- posterior lobe (neural tissue and stores hormones)
- anterior lobe (glandular tissue and produces hormones such as TSH, ACTH, FSH, LH, GH, PRL)
Oxytocin
- induces labour and lactation
- produced in hypothalamus, secreted by posterior pituitary gland.
Thyroid stimulating hormone (TSH)
stimulates the thyroid gland
Adrenocorticotropic Hormone (ACTH)
stimulates the cortex of the adrenal glands
Follicle-stimulating hormone (FSH)
- controls growth and functioning of gonads.
- females: initiates development of Graafian follicle.
- males: initiates spermatogenesis.
Lutenizing hormone
- promotes production of gonadal growth
- females: acts with FSH to mature Graafian follicle and triggers ovulation and causes formation of corpus luteum.
- males: cause Leydig cells to secrete testosterone
growth hormone
- promotes growth of all the tissues in the body. (bones and skeletal muscles)
- works with glucagon to increase blood glucose levels.
prolactin
stimulates milk production
thyroid gland
- simple cuboidal epithelium
- produce colloidal which contains thyroglobin.
- hormones: thryroxine, triiodothyroxine, Calcitonin
thyroid with a goiter
due to a lack of dietary iodine, cells produce colloid but cannot iodinate it and make functional hormones. TSH is still produced causing enlargement of the thyroid gland.
adrenal gland
- produces hormones called corticosteroids
- layers:
- capsule that protects and attaches adrenal gland
- adrenal cortex: Zona glomerulosa, zona fasiculata, zona reticularis
- adrenal medulla
zona glomerulosa
secretes mineralocorticoids and produces aldosterone
zona fasiculata
secrete glucocorticoids (cortisol)
zona reticularis
adrenal androgen’s are secreted here
adrenal medulla
secretes the hormones epinephrine and norepinephrine
pancreas- (Islets of Langerhans)
insulin and glucagon are released from the islets of Langerhans.
insulin
- lowers blood glucose levels.
- released by Beta cells
- insufficient insulin production=type 1 diabetes
- reduction of insulin’s effectiveness on target tissue = type 2 diabetes
hyperinsulinism
when there is too much insulin, which lowers the blood glucose levels, and causes the brain to not be able to function properly.
glucagon
- raises the blood glucose level
- released by alpha cells
