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. What is main difference is signal transmission in nicotinic vs muscarinic?
***nicotinic is ionotropic; muscarinic is GPCR
Liposome has phospholipid bilayer
Inner lining of blood vessels
Comes into play in the large intestine - where vitamin b12 is absorbed w/help of E. coli; thus; must travel thru bloodstream to large intestine


2. Meiosis II: EQUATIONAL DIVISION
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Prophase II: no crossing over b/c there are no homologous chromosomes; nuclear envelope dissolves Metaphase II: chromosomes line up at metaphase plate Anaphase II: sister chromatids separate - migrate to opp poles Telophase II: nuclear envelope reap
Outermost layer of blood vessel
Neurons may perform one of three functions....


3. review: parietals secrete intrinsic factor...
Comes into play in the large intestine - where vitamin b12 is absorbed w/help of E. coli; thus; must travel thru bloodstream to large intestine
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Contain capillary network - lymph vessels (lacteals)


4. How do nutrients move?
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
Vitamin K - b12 - thiamin - riboflavin


5. physiology of gall bladder - liver and pancreatic secretions
Carry signals to musc OR Gland
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
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded


6. 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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7. signal transduction occurs by 2 paths
1) by integral ion channels 2) transmitted by second messenger system
Normally contracted
Low because AAs are immediately used in translation
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest


8. Where does blood to be filtered by kidney enter the nephron?

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9. Some PNS nerves are found in brain - spinal cord
Direction of differentiation
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue


10. these transport proteins - when concs are high enough...
Night vision
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
Regulated by gastrointestinal horms
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine


11. lining of abdominal cavity=
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Eukaryotes
An endogenous morphine
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid


12. Seen in lysosomal storage diseases
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Amino acid monomers - di - tri absorbed by symport at enterocyte; each AA has slightly diff mechanism; from entero - AAs enter bloodstream where they are taken up by all cells of the body - esp the liver by active or facilitated transport (NEVER PASS
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)


13. spermatogonia arise from
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Needs time for bile - lipase - micelle migration - enterocyte uptake
Epithelial tissue near semniferous tubules
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics


14. On what surface of the retina is the eye most sensitive
Fovea (highest amount of cones)
Raises BP; causes collecting ducts at end of nephron (kidney) to become permeable to water - which concentrates urine; coffee - beer block ADH and increase urine volume
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue


15. The EYE
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Pancreatic duct (made of acinar cells?)
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)


16. A pinpoint iris is contracted or uncontracted
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
Uncontracted: parasymp (eg opoid use)
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)


17. Ovum development is halted At what stage until fertilization...
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
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)


18. protein absorption at enterocyte
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Amino acid monomers - di - tri absorbed by symport at enterocyte; each AA has slightly diff mechanism; from entero - AAs enter bloodstream where they are taken up by all cells of the body - esp the liver by active or facilitated transport (NEVER PASS


19. Kidney
Adrenal gland -- AC: steroids (cortisol - aldosterone); AM: catecholamines (epi - norepi); Islets of langerhans: peptides (insulin/glucagon) ANTAGONISTS: calcitonin (thyroid - peptide lowers Ca in blood); parathyroid hormone - peptide - vitamin D pat
Albumin increases osmolarity of blood; increases osmotic pressure
Excretes waste products: urea - uric acid - ammonia - phosphate - maintains homeostasis: including body fluid volume (water reabsorption) and solute composition (mineral balance - nutrient reabsorption) - controls *plasma* pH: antiport of Na/K and pr
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity


20. 80-90% fat absorbed this way
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Paracrine (local) - endocrine (longer distance)
Prophase II: no crossing over b/c there are no homologous chromosomes; nuclear envelope dissolves Metaphase II: chromosomes line up at metaphase plate Anaphase II: sister chromatids separate - migrate to opp poles Telophase II: nuclear envelope reap


21. 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
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on


22. FSH - LH - HCG - inhibin are...
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
Smooth ER
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Peptides


23. components of interstitial fluid
Glycosaminoglycans - prots - AAs - lipids
Epithelial tissue near semniferous tubules
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
Has memb - bound organelles - etc...


24. Leydig cells produce
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)
Testosterone upon stim by LH
Vitamin K - b12 - thiamin - riboflavin


25. parathyroid hormones
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
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... ...
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
In gastric pits; secretions combine into gastric juice


26. Different organs working together
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Systems (eg digestive system consists of many organs)
Glands w/ducts: Exocrine glands
Follicular phase: primary - secondary - ovulation (1 week) luteal phase: ovulation - thickening of uterine lining w/corpus luteum secretion - corpus luteum degrades (2 weeks) flow: shedding of uterine lining (4 days)


27. How does water cross the apical membrane
Thru tight junctions by favorable osmotic gradient
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity


28. cytosol pH
About 7.2
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Glucose = aldose fructose = ketose
Night vision


29. extracellular matrix formed mainly of...
Paracrine (local) - endocrine (longer distance)
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
Digestion


30. smooth ER main function
Faces the lumen
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
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Excretes waste products: urea - uric acid - ammonia - phosphate - maintains homeostasis: including body fluid volume (water reabsorption) and solute composition (mineral balance - nutrient reabsorption) - controls *plasma* pH: antiport of Na/K and pr


31. What are phagosomes
Membrane - bound - endocytosed bodies
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Below hypothalamus
Break down TAGs to monoglycerides and free fatty acids


32. fructose enters enterocyte by
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
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Facilitated diffusion: no symport w/ secondary transport
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)


33. keep in mind that enterocyte is like a regular euk cell
Has memb - bound organelles - etc...
Regulated by gastrointestinal horms
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state


34. STOMACH: no absorption
Neurons may perform one of three functions....
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Glucose
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching


35. Creating gradients requires what?
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
Lowers osmolarity of the filtrate (IONS - Water Are Taken Back Up By The Kidney)--->at the end of the distal tubule (the collecting tubule) is where aldosterone acts - along with the JGA
Faces the lumen
Estradiol


36. quote on cavities/viscera

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37. Sensory - motor neurons are part of which nervous system
Peripheral nervous sys
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
About 7.2


38. position of AP...
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Below hypothalamus


39. lysosome main function and derivation
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Sensory (afferent - dorsal) - motor (efferent - ventral)
Most absorption occurs in sm intestine
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi


40. Path of urine

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41. In IBS - What is defective

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42. Alpha - amylase found where
Outermost layer of blood vessel
In mouth - breakdown of starch into polysaccharides
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide


43. food in duod stims release of gastrointestinal hormones
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Oxytocin and ADH (aka vasopressin)


44. What is a toxic byproduct of gluconeogenesis from proteins
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Sorts - modifies - concentrates proteins from the ER
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)


45. Adrenal medulla hormones (TYR- DERIVED)
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Thru tight junctions by favorable osmotic gradient
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons


46. Neuronal cell bodies have extensions ie
Prophase II: no crossing over b/c there are no homologous chromosomes; nuclear envelope dissolves Metaphase II: chromosomes line up at metaphase plate Anaphase II: sister chromatids separate - migrate to opp poles Telophase II: nuclear envelope reap
Growth 1 (G1) phase: STRUCTURAL ProteinS - ENZYMES; This is a very active period - where the cell synthesizes its vast array of proteins - including the enzymes and structural proteins it will need for growth. In G1 stage each of the chromosomes cons
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Processes: axons - dendrites


47. lysosome pH
Comes into play in the large intestine - where vitamin b12 is absorbed w/help of E. coli; thus; must travel thru bloodstream to large intestine
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
5
Alpha 1-4 and 1-6 (branching) glycosidic linkages


48. Where do absorbed fats go in the enterocyte
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Within the paravertebral ganglion - running parallel to spinal cord
Mostly reabsorbed to liver
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles


49. Interaction of corpus luteum/placenta
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Below hypothalamus
Glucose and ketone bodies (not from glycogen stores)
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions


50. How is the follicle developed during oogenesis
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Oxytocin and ADH (aka vasopressin)
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Only musc and esp ** liver can store large amounts