MCAT Biology - Homeostasis (Excretory and Integumentary Systems)
Approximately 20% of blood that passes through the glomerulus is filtered into what space?
Bowman's
What cup-like structure surrounds the glomerulus?
Bowman's capsule
What is the functional unit of the kidney?
nephron
What layer of the skin consists of loose CT?
papillary layer of the dermis
What are the two layers of the dermis?
papillary, reticular
The renal pelvis narrows to form what structure?
ureter
What is the name of the capillary bed formed from the efferent arterioles?
vasa recta
What two structures create a countercurrent multiplier system?
vasa recta, nephron
Where do all nephrons empty into?
renal pelvis
Name four functions of the excretory system.
BP, blood osmolarity, acid-base balance, nitrogenous waste
If the blood is acidic, the kidneys will excrete more of what?
H+
What does the PCT secrete?
H+, urea, NH3, K+
As part of the renal portal system, the renal artery branches out, passes through the medulla, and enters the cortex as what structure?
afferent arterioles
The DCT responds to what hormone?
aldosterone
The collecting duct responds to what hormone?
aldosterone and ADH
What is reabsorbed in the PCT?
amino acids, glucose, water-soluble vitamins, salts and water
In which layer of the epidermis are melanocytes located?
basale
In which layer of the epidermis do you find stem cells?
basale
In which layer of the epidermis does the proliferation of keratinocytes occur?
basale
The ureter enters into what?
bladder
In which layer of the epidermis can you find several layers of flattened keratinocytes?
corneum
What is the name of the kidney's outermost layer?
cortex
What is the name of the muscular lining of the bladder?
detrusor
What is the name of the thicker part of the loop of Henle which occurs at the transition from inner to outer medulla?
diluting segment
What part receives blood from the glomerulus and then forms a second capillary bed?
efferent arterioles
What are the three functions of the kidney?
filtration, secretion, reasborption
What structure is a highly convoluted capillary tuft that is derived from the afferent arterioles?
glomeruli
What molecules are almost always reabsorbed?
glucose, amino acids, vitamins
In which layer of the epidermis do keratinocytes begin to die and lose their nuclei?
granulosum
Hydrostatic pressure in the glomerulus is ____ than that in Bowman's space, which causes fluid to move into the nephrone.
higher
The osmolarity of blood is ___ than that of Bowman's space, resulting in pressure opposing the movement of fluid into the nephron.
higher
Hydrostatic pressure is ___ than oncotic pressure, so net flow is from ___ to ___.
higher, blood, nephron
At the diluting segment, filtrate becomes hypertonic, isotonic, or hypotonic?
hypotonic
There are two urethral sphincters, which one consists of smooth muscle and is therefore under involuntary control?
internal
Filtrate is ___ to blood.
isotonic
In the PCT, is the filtrate hypertonic, isotonic, or hypotonic?
isotonic
Calluses form from excessive ___ deposition in areas of repeated strain due to friction to provide protection against future damage.
keratin
What is the name of the kidney's inner layer?
medulla
What sensory receptor responds to light touch?
meissner's corpuscles
What cell in the skin is derived from neural crest cells?
melanocytes
What sensory receptor responds to deep pressure and texture sensation?
merkel cells
What is the reflex called in which stretch receptors in the bladder convey to the nervous system that the bladder needs emptying?
micturition
What sensory receptor responds to deep pressure and vibration?
pacinian corpuscles
What three structures enter and exit through the renal hilum?
renal artery, renal vein, ureter
What is the name of the deep slit in the center of the kidney's medial surface?
renal hilum
What sensory receptor responds to stretch?
ruffini endings
What is the ascending loop of Henle permeable to?
salts
The diluting segment is surrounded by larger cells with large amounts of mitochondria to encourage reasborption of what?
sodium, chloride
In which layer of the epidermis do keratinocytes become connected to each other?
spinosum
In which layer of the epidermis is the site for Langerhans cells?
spinosum
Does piloerection help keep you warm or cool?
warm
The DCT is the site of ___.
waste secretion
What is the descending loop of Henle permeable to?
water
