final Flashcards
(64 cards)
Where does Filtration happen and from which arteriole
Glomerulus and the Bowmans capsule
blood is received from the Afferent arteriole
Layers of the filtration membrane and their roles
- Fenestrated endothelium of glomerular capilaries
–> has pores to allow small things through, but BLOCKS blood cells - basement membrane
–> filters based on size and negative charge, blocking Large proteins - podocytes of bowman’s capsule
–> specialized cells with flits that further filter what enters the capsule
What gets flitered initially?
allowed:
- Water
- Na+, K+,Cl-
- Glucose
- Amino Acids
- Urea
- Creatine
Not:
- Plasma Proteins
- Blood Cells
What is the GFR regulated by
- Blood pressure
- blood volume
- constriction dilation of afferent and efferent arteriols
- hormones : renin, AT II and ANP
GLomerular Filtration takes place in?
renal corpuscle
Regulation of filtration:
Intrinsic
myogenic mechanism:
Afferent arteriole constricts when BP increases to reduce GFR
tubuloglomerular feedback:
Macula senses NaCl in distal tubule, signlas afferent arteriole to constrict if GFR is too high.
Regulation of filtration:
Extrinsic Regulation
- sympathetic nervous system
Norepinephrine is released
Causes vasoconstriction of the afferent arteriole
↓ GFR to conserve fluids
Also stimulates renin release from juxtaglomerular cells
→ which leads to RAAS activation 🔁
- RAAS
Activated by low blood pressure, low sodium, or SNS stimulation
Steps:
Renin released from JG cells
Converts angiotensinogen → angiotensin I
ACE (from lungs) converts I → angiotensin II
Angiotensin II does 3 things:
Vasoconstricts → ↑ BP
Stimulates aldosterone → ↑ Na⁺ & water reabsorption
Stimulates ADH → ↑ water reabsorption
Reabsorption:
what happens at PCT
- filtrat Na+, Cl-, glucose, amino acids, water
Uses active transport
Reabsorption at the loop of henle
water gets reasbosrbed @ descending limb
Na+/Cl- gets reabsorbed at ascending limb.
Creates concentration gradient in medulla
what gets reabsorbed at DCT
Na+, Cl- , Ca2+ (regulated by hormones)
What gets reabsorbed at collecting duct
Water (via ADH), Na+ (via aldosterone) , Urea
Tubular Reasborption Routes:
- Transcellular
- Paracellular
Transceullar route
- transport across apical membrane
- diffusion through cytosol
- transport across basolateral membrane
- movement thrugh interstitial fluid and into capillary - enters blood through endothelium of peritubular capplilares
Paracellular
- between tubule cells
- limited by tight junctions, but leaky in proximal nephron
- water, ca2+, mg2+ k+ move through this route v
Ordering the stages of spermatogenesis
Spermatogonia → Primary spermatocyte → Secondary spermatocyte → Spermatid → Spermatozoa
spermatogonia
type A & type B daughters
type B develops into primary spermatocytes
secondary spermatocytes (meiosis I)
spermatids (meiosis II)
spermatozoa (shed cytoplasm, form flagellum)
Ovarian ligament
anchors ovary medially to uterus
Broad Ligament
Supports blood vessels, ureter, uterine , utersus, vagina
Round ligament
bind uterus to anterior wall
Ovaries are surrounded by?
fibrous tunica albuginae (cuboidal epithelium)
Ovarian
Follicle cells vs Granulosa Cells
Follicle cells: oocyte is only one cell layer is present)
Granulosa Cells: If more than one layer presesnt
Follicles stages
- primordial follicle: single layer + oocyte
- primary & secondary follicle: several layers of granulosa cells + oocyte
- vesicular follicle : fully mature follicle
What is corpus luteum?
a temporary endocrine gland that forms in the ovary after ovulation
Female Duct system includes?
- Fallopian tubes
- Uterus
- Vagina