MCAT Prep - 2

Instructions:

• Answer 50 questions in 15 minutes.
• If you are not ready to take this test, you can study here.
• Match each statement with the correct term.
• Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. gradual increase in FSH typical of primary follicle development;
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)


2. What is a toxic byproduct of gluconeogenesis from proteins
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Primitive streak - which consists of cells of the MESODERM ****
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Size of fist; two kidneys; have cortex (steroid hormones) and medulla (catecholamines) - receives about 20% of cardiac output - blood travels down arteries - up veins -'urine is created by the kidney and emptied into the renal pelvis - which is empti


3. After meiosis II - Male

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4. Where else does ADH act
Glucose and ketone bodies (not from glycogen stores)
- filtration occurs at the fenestrations of the renal corpuscle - most reabsorption and secretion occur in the proximal tubule - medulla is concentrated in the loop of henle - sodium and calcium are reabsorbed in the distal tubule -->collecting tubul
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Primitive streak - which consists of cells of the MESODERM ****


5. Sensory - motor neurons are part of which nervous system
Inner lining of circulatory system
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Peripheral nervous sys


6. peroxisome is derived from this
ER
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
***starting with adipose tiss: FFAs are transported in the blood by albumin (major component of blood plasma); one albumin typically carries three fatty acid molecules but can hold up to 30 FAs
- parietal cells (**oxyntic= hi oxygen consumption - hi E??): have hi conc mito; need lots of energy to create proton gradient; thus - responsible for extremely harsh pH conditions in stom; denaturing conditions - chief cells (peptic): synthesize pep


7. microvilli: increase SA of enterocyte; have hi conc of digestive enzymes

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8. 80% of end product of carbohydrate metabolism is...
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Glucose
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion


9. Thus inhibiting parietal cells could do What to blood pH
In mouth - breakdown of starch into polysaccharides
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Lower blood pH
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)


10. Blastocyst
After 4 day+ - morula cells have formed fluid - filled ball (blastocyst); this implants in uterus at day 5-7; blastocyst is made up of EMBRYONIC STEM Cells; once implanted w/blastocyst - female is pregnant
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Peptide; stims growth of nearly all cell of body; all other anterior pituitary horms have specific targets; upregulates anabolic pathways; use of fat for energy goes up (fat - burning); increases AA transport across cell membrane (nutrient uptake)
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)


11. What is the path of a sound wave that enters the ear?
Chylomicrons are much bigger
About 7.2
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Outer ear= pinna (auricle)- external auditory canal - eardrum (tympanic membrane) inner ear= malleus - incus - stapes - ...oval window - cochlea - where sound is transduced into neural signal...enters cochlea at scala vestibuli - where pressure chang


12. smooth ER main function
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Mostly reabsorbed to liver


13. Different organs working together
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Systems (eg digestive system consists of many organs)
Form barrier to extracellular fluid
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase


14. What controls release of LH - FSH from anterior pituitary
1) by integral ion channels 2) transmitted by second messenger system
Oxytocin and ADH (aka vasopressin)
Gonadotropin releasing hormone - GnRH
Liposome has phospholipid bilayer


15. The esophageal sphincter is...
Normally contracted
Systems (eg digestive system consists of many organs)
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals


16. FSH - LH - HCG - inhibin are...
Only musc and esp ** liver can store large amounts
Gastrulation occurs: formation of three primary germ layers = differentiation
Peptides
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity


17. going down the loop of Henle - water - permeable - filtrate osmolarity goes up as water leaves...
In gastric pits; secretions combine into gastric juice
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Processes: axons - dendrites
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves


18. FLAT PG: ACTH
Form barrier to extracellular fluid
Nitrogen
Stomach - sm intest - spleen - pancreas from the hepatic portal vein...all blood that passes thru liver go thru flattened spaces called the ***hepatic sinusoids -->hepatic vein --->vena cava
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP


19. medium for paracrine hormones
Pepsin - secreted by chief cells in the stomach epithelial lining and active at low pH - breaks down proteins to polypeptides. Protein hydrolysis is aided by the highly acidic environment (hi gastric acid from parietal cells). Polypeptides are squirt
Interstitial fluid (eg prostaglandins - cytokines)
Outer ear= pinna (auricle)- external auditory canal - eardrum (tympanic membrane) inner ear= malleus - incus - stapes - ...oval window - cochlea - where sound is transduced into neural signal...enters cochlea at scala vestibuli - where pressure chang
Neurons may perform one of three functions....


20. portal vein physiology...

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21. what else is located in the inner ear (not directly related to auditory)
Steroid; target tissue is distal convoluted tubule of nephron and collecting duct; increases blood mineral concentration; potassium - protons secreted (blood pH increases); sodium - chloride reabsorbed (BP increases)
Two perpendicular semicircular canals involved in balance - equilibrium
Small intestine; duodenum is smallest and does most DIGESTION; jejunum is medium and does most ABSORPTION; ileum is biggest and does most absorption along with jejunum
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching


22. Where does the bolus go after mouth chews food
Glands w/ducts: Exocrine glands
Hormones --->stimulate exocrine glands - acetylcholine (increases all secretion of gastric pits) - gastrin (from G cells) - histamine (increases HCl secretion of parietals) ...Ach increases all secretions; gastrin increases gastric acid (parietal cel
Uncontracted: parasymp (eg opoid use)
Moves down thru esophageal sphincter


23. What is somatostatin
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Processes: axons - dendrites


24. On what surface of the retina is the eye most sensitive
Fovea (highest amount of cones)
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Increases surface area of food ball (bolus)


25. overall - fatty - prot - rich food in duod causes
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
vitreous humor - retina - fovea
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility


26. in fat and liver cells monoglycerides and ffas are once again
Stores blood: when expanded liver serves as blood reservoir for body - filters blood: Kupfer cells phagocytize bacteria picked up from intestines - destroys bad RBCs: also done by Kupfer cells - detoxifies blood: detoxified chemicals are excreted eit
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver


27. Three stages of the menstrual cycle
Nitrogen
In liver (RBC recycling of heme); stored in gall bladder; released via cystic duct to common bile duct (shared w/liver); common bile duct joins up with panc duct...everything feeds into the sm intest at the ampulla of vater**
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5


28. STOMACH: no absorption
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Ventrally (picture skeletal vertebrae)
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)


29. Kidney physiology...

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30. What is a nerve? (PNS)
Called a tract in the CNS; bundling together of axons/dendrites thru which many diff signals pass; many many neurons are bundled together into a single nerve
REABSORPTION: draws off water and ions - increases osmolarity of the medulla while slightly lowering osmolarity of the filtrate -->medulla must have hi osmolarity in order to concentrate urine at collecting duct (final step in nephron)
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Monitors filtrate pressure in the distal tubule; has specialized cells (granular cells) that secrete an enzyme (**renin); renin initiates regulatory cascade that produces angiotensin I - II - III that stim adrenal cortex to secrete aldosterone... ...


31. Important of villi (='shaggy hair') More fluid makes contact with the epithelial tissue: thus nutrients in solution have less distance to travel to diffuse into villi.

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32. bundles of collecting ducts are called
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Urine enters kidneys via artery - to arteriole - capillary bed - glomerulus - Bowman's capsule - proximal tubule - loop of henle (concentrates medulla) - distal tubule - collecting tubule - collecting duct (renal pyramids) - renal calyx - renal pelvi
Contain capillary network - lymph vessels (lacteals)
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome


33. What Changes - Doesn't Change as a result of movement of molecules across membranes in the proximal tubule
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
- enterocytes w/ *microvilli brush border*: membrane - bound digestive enzymes for carbs - fats - nucleic acids - goblet cells: secrete mucous - Deep between villi are the intestinal exocrine glands - the crypts of Lieberkuhn - which secrete pH 7.6 i
Combined via conjunction of pancreatic duct and common bile duct; common bile duct originates at **cystic duct where gall bladder and liver secretions combine ..cystic duct+common bile duct+pancreatic duct --->into duodenum
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males


34. Polypeptides are formed with what kind of reaction?
1) by integral ion channels 2) transmitted by second messenger system
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Zygotes are diploid
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid


35. calcitonin

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36. Does bile digest fat?
Facilitated diffusion from hi to lo conc
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase


37. For focal point that is nearby - what will the lens look like
Lysosome
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins


38. serous membranes have a viscera - facing layer and a body wall - facing layer
Work together to emulsify fats: bile works as a detergent to increase SA of the fat; increased SA gives more substrate to lipase for digestion
visual (rhodopsin is receptor - derived from Vit A; conformation change occurs with photon to hyperpolarize rod cells; cone cells use photopsin for receptor) - olfactory - mood (NTs targeted by antidepressants - antipsychotics - etc; GABA is inhibit
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity


39. So - following blastocyst implantation (4d) - at approx 2 weeks past fertilization
Carry signals to musc OR Gland
Gastrulation occurs: formation of three primary germ layers = differentiation
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
- filtration occurs at the fenestrations of the renal corpuscle - most reabsorption and secretion occur in the proximal tubule - medulla is concentrated in the loop of henle - sodium and calcium are reabsorbed in the distal tubule -->collecting tubul


40. important pancreatic enzymes
Stom= G cells (gastrin) - parietal (oxyntic); chief (peptic); mucous cells (hi ER - Golgi to make sticky glycoprots) - sm intest= enterocytes (w/brush border of maltase - sucrase - lactase - dextrinase; peptidase; lipase; nucleases); goblet cells (mu
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase


41. what happens when glycogen stores are saturated and blood sugar remains high?
Lots of energy; eg neurons have hi glucose need for 3Na out 2K in ATPase; stomach epithel tiss needs E for parietal cells to pump protons into lumen and bicarbonate into blood
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Increases blood Calcium


42. light detection via GPCRs
90-140 mg/dl
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)


43. oxytocin
The wall of the body or of a body cavity or hollow structure
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Systems (eg digestive system consists of many organs)


44. FLAT PG: LH
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Steroid; target tissue is distal convoluted tubule of nephron and collecting duct; increases blood mineral concentration; potassium - protons secreted (blood pH increases); sodium - chloride reabsorbed (BP increases)
Peptide; responsible for luteal surge (driven in part by LH-->testosterone -->estradiol -->LH positive feedback); results in ovulation (follicle bursting) - releasing egg into fallopian tube/oviduct
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc


45. PNS is broken down into
Small intestine; duodenum is smallest and does most DIGESTION; jejunum is medium and does most ABSORPTION; ileum is biggest and does most absorption along with jejunum
Eukaryotes
Somatic nervous sys - autonomic nervous sys
Stims release of tyrosine - derived horms T3/T4 (increase basal metabolic rate); TSH increases thyroid cell size - number - rate of T3/T4 synth -----> thus - iodine deficiency causes swollen thyroid due to lack of neg feedback onto TSH in anterior pi


46. What is feces composed of...
Signal picked up by sensory cell - goes thru dorsal root ganglion to SC - may continue to interneurons in brain or simple reflex arc in SC - brain integrates info and decides (voluntary) response - travels back down SC to appropriate ventral root gan
Testosterone upon stim by LH
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
75% water/ 25% solid mass: of that solid mass: 10-20% fat = phospholipid bilayer of bacteria - slough - off enterocytes ie stomach lining (must be constantly rebuilt) 10-20% inorganic material 30% roughage = fiber = cellulose (indigestible) 2-3% prot


47. SYMP neurons originate in= PARA neurons originate in=
Conjunction of cell body w/axon
***starting with adipose tiss: FFAs are transported in the blood by albumin (major component of blood plasma); one albumin typically carries three fatty acid molecules but can hold up to 30 FAs
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
SYMP: spinal cord --->paravetebral ganglion PARA: spinal cord - brain; cell processes --->ganglion near effector organ (preganglionic neurons) extend outside of spinal cord to synapse at ganglia - go on along postganglionic neurons


48. What are the memb - bound enzymes of the brush border?
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
About 7.2
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases


49. components of interstitial fluid
Glycosaminoglycans - prots - AAs - lipids
Increases surface area of food ball (bolus)
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Digestion


50. What do villli do
Stom= G cells (gastrin) - parietal (oxyntic); chief (peptic); mucous cells (hi ER - Golgi to make sticky glycoprots) - sm intest= enterocytes (w/brush border of maltase - sucrase - lactase - dextrinase; peptidase; lipase; nucleases); goblet cells (mu
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Digestion
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra