renal and urogenital system Flashcards
what is the job of the kidneys
to regulate the composition of the blood
what is osmoregulation
the maintenance of the balance between water and electrolytes in the body’s fluid
how many litres of blood do kidneys filter every 24 hours
150
what blood vessel does the kidney receive blood from
the renal artery
what blood vessel does the kidney use to return the blood back to the body
renal vein
what are the 3 layers of connective tissue that protect the kidneys
renal capsule (I), adipose capsule (M), renal fascia (O)
where is the renal pelvis located
the centre of the kidney
what are the features of the renal vein
large diameter and thin wall
why must the blood being supplied to the kidney contain glucose
to provide the kidney with energy to produce urine
what is the role of the renal pelvis
region of the kidney where urine collects
how are kidney stones formed
when the salts in urine crystalise to form a solid mass which prevents urine draining out of the medulla of the kidney
what is the role of the ureters
they carry blood down to the bladder
what is the role of the renal medulla
where the amount of salt and water in urine is controlled
what does the renal medulla consist of
billions of loops of Henle, that pump sodium ions
how if the renal medulla visually different to the rest of the kidney
its a very dark red colour
what is ADHs effect on the loops of Henle
it stimulates the loops to work harder to pump more sodium ions, making the urine more concentrated
what’s an example of a diuretic
alcohol and tea
what is included in the nephron structure
bowman’s capsule, Glomerulus, loop of Henle and the collecting duct
how many nephrons are in each kidney
1-2 million
what is the glomerulus
a capillary network in the bowman’s capsule, blood leaving here passes into a second capillary network
what are the features of the proximal convoluted tubule
coiled and lined with cells carpeted with microvilli and stuffed with mitochondria
what is the collecting duct
leads to the pelvis of the kidney from where urine flows to the bladder
what is the sequence of flow within the nephron
bowman’s capsule - proximal convoluted tubule - loop of Henle - Descending loop - Ascending loop - distal convoluted tubule - collecting duct - renal pelvis - ureter - bladder - urethra
what are the 3 processes involved in the formation of urine
simple filtration, selective reabsorption, secretion
what are the 3 layers of the bladder
transitional epithelium (I), Smooth muscle and elastic fibres (M), loose connective tissue (O)
what is urine made of
water and nitrogenous wastes such as urea, salts and metabolites from endogenous and exogenous sources
what is an exogenous source
produced outside the body e.g. drugs
what is an endogenous source
produced in the body
how much urine is produced a day (normally)
over a litre
what is urines pH range
4-8.5
what happens when more water is lost by the body through sweat
triggers the release in ADH into the blood which acts on the cells of the distal tubule to reabsorb more water to reduce the amount lost via excretion
what happens if there is too much water in the body
ADH levels are reduced to limit the amount of water reabsorbed back into the body, and increasing the amount that is excreted in urine
ADH is known as
vasopressin
what happens to the DCT and the collecting duct as ADH levels rise
they become more permeable to water, allowing more to be reabsorbed back into the body
what is ADH secreted from
the pituitary glands
what signals the release of ADH to the pituitary glands
osmoreceptors in the hypothalamus sense the Na+ concentration of the blood (the nerve endings of these osmoreceptors are located in the posterior pituitary gland
is ADH secreted by osmoreceptors when Na+ concentration of the blood is low or high
high
what 3 hormones does the kidney release
erythropoietin, Renin, Calcitriol
what effect does erythropoietin have on the body
stimulates bone marrow to make red blood cells
what effect does renin have on the body
regulates blood pressure
what effect does calcitriol have on the body
the active form of vitamin D which helps maintain calcium for bones and for normal chemical balance
what does renin act on
angiotensinogen which is a plasma peptide, splitting off a fragment containing 10 amino acids called angiotensin.
what happens to angiotensin I
its cleaved by a peptidase that’s been secreted by the blood vessels called angiotensin converting enzyme, producing angiotensin II
what is the role of angiotensin II
It constricts the walls of arterioles
stimulates the PCT to reabsorb Na+
increases the strength of the heartbeat
stimulates the pituitary to release the vasopressin
(all of which lead to an increase in blood pressure)
when aldosterone levels are high what happens to the remaining Na+
its actively reabsorbed
what does the juxtaglomerular apparatus release renin in response to?
sympathetic nervous system stimulation
decrease filtrate osmolarity
decreased stretch due to decrease in BP
what does renin catalyse
the production of angiotensin II which prompts aldosterone release
what is oestrogens influence on sodium balance
enhances NaCl reabsorption by renal tubules, may cause water retention during menstrual cycles, are responsible for edema during pregnancy
what is progesterone’s influence on sodium balance
decreases sodium reabsorption, acts as a diuretic, promoting sodium and water loss
what is glucocorticoids influence on sodium balance
enhances reabsorption of sodium and promotes oedema
what does the blood pressure of your body depend of
the force of the contractions of the heart - relates to how much the heart muscles get stretched by the incoming blood, the degree to which the arteries and arterioles constrict - increases the resistance of blood flow thus requiring a higher blood pressure
how does the kidney influence blood pressure
causes arteries and veins to constrict, increasing and decreasing the circulating blood volume
what hormones does the adrenal glands produce
adrenaline, noradrenaline, cortisol and aldosterone
what is the role of aldosterone
helps regulate the body’s water balance
