Final - Urinary Flashcards
What are the components of the urinary system and their functions?
- kidneys (conserve body fluids and electrolytes; remove metabolic wastes; endocrine functions)
- ureters (transport urine from kidney to bladder)
- bladder (store urine)
- urethra (excretion of urine)
Components of the kidney structure (4)
- capsule of CT
- cortex (has renal corpuscle)
- medullary rays
- medulla (mainly tubes) with pyramids
What is a nephron?
functional unit of kidney (collects urine and secretes it)
Describe the histology of the kidney capsule and its functions
- outer layer fibroblasts and collagen
- inner layer with myofibroblasts (contractibility aids in resisting volume pressure changes that vary with kidney function)
Describe the anatomical structure of a nephron of the kidney (2 parts)
- renal corpuscle (glomerulus with capillary tuft and Bowmans capsule)
- tubular portion
Describe the flow of filtrate from the glomerulus to the medullary collecting duct.
glomerulus-> proximal convoluted tubule -> proximal straight tubule -> thin loop Henle -> distal straight tubule -> distal convoluted tubule -> collecting tubule -> collecting ducts
What is a renal corpuscle and where would you find it in a section of the kidney?
house fenestrated capillaries for blood filtration and is found in the cortex
Describe Bowman’s capsule and explain podocyte relevance/function.
Fx: filtration
- parietal layer - simple squamous epithelium
- visceral layer - podocytes that create filtration slits
How would you describe the histology of the capillaries in a renal corpuscle?
They are fenestrated/discontinuous and are larger, irregular, and more numerous than other capillaries for filtration
What are the functions of mesangium?
- phagocytosis (keep large proteins from blocking cells)
- structural support
- secreting
Where do you find the mesangium?
in the glomerulus?
What are the cell types associated with the mesangium?
- mesangial cells: within basal lamina of the glomerulus
- Lacis cells: along vascular pole
Describe the function of the juxtaglomerular apparatus
senses blood volume and tubular fluid composition (endocrine)
What is the purpose of the juxtaglomerular apparatus?
regulate blood pressure by activating renin-angiotensin-aldosterone system (RAAS)
Describe RAAS
- low blood volume
- juxtaglomerular cells make renin (acid protease)
- renin converts angiotensinogen -> antiotensin I
- angiotensin I -> angiotensin II conversion by ACE on lung endothelial cells
- angiotensin II stimulates release of aldosterone from adrenal glands to constrict blood vessels
- aldosterone increases reabsorption of Na & H2O at collecting ducts
Where would you find a lumen of a PCT in a kidney section?
cortex - star-shaped lumen with cubed cells
Where would you find the lumens of the segments of Henle’s loop?
medulla
Where would you find a lumen of the DCT?
in both the medulla and cortex… but mainly medulla - circular lumen that is simple cuboidal
Collecting duct function
deals with water - how much to reuptake and how much to leave in the interstitial space (in medulla)
Where does renal blood supply enter and exit the kidney, anatomically?
renal pelvis
Beginning with the minor calyx and ending with the urinary bladder, which histological layers are present?
- all have transitional epithelium
- all have mucosa and muscularis (inner longitudinal + outer circular) with adventitia/serosa
How would you describe the mucosa of the excretory regions?
transitional epithelium when stretched flat, when collapsed, dome-shaped
Describe the muscularis of the excretory regions.
inner longitudinal and outer-circular
What is the trigone in the urinary bladder?
triangular region with three openings has sympathetic, parasympathetic, and sensory fibers for nerve specialization
For the urethra, compare the male and female urethra mucosal layers.
M: has glands (cowpers & glands of Littre) - urethra changes transitional -> stratified columnar -> stratified squamous)
F: has paraurethral glands (alkaline secretion) & more continuous (transfers to stratified squamous only at urethral opening)
Would one expect to find striated muscle in the urethra?
Yes, because you can hold it in when going to the bathroom and flow rate
Now that you have studied RAAS, explain what an ACE inhibitor is and why it is given to patients with hypertension?
In the lungs, ACE converts angiotensin I to II which then goes on to stimulate the release of aldosterone which increases the resorption of Na and H2O and leads to an increase in bp… by blocking ACE this conversion stops in the lungs and bp is not increased
Now that you have seen the RAAS pathway, explain why having extra white adipose (being obese/overweight) is associated with higher risk of hypertension.
“white adipose tissue is the most abundant source of angiotensin after the liver” — leads to the activation of RAAS pathway and an increase in bp
