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. Between meals most fats appear in blood as
- 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
An endogenous morphine
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc


2. cholinergic receptors: NICTONIC and MUSCARINIC Nicotinic: neuromuscular effectors (ionotropic) Muscarinic: PARA effectors (GPCRs) Adrenergic: SYMP effectors (GPCRs)
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors


3. Where do absorbed fats go in the enterocyte
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Interstitial fluid (eg prostaglandins - cytokines)
Collection of cell bodies; cell processes project out from both ends of ganglion; synapses with interneuron in spinal cord on one end and sensory receptor on other
Presence of fat - prot in duodenum causes release of **gastric inhibitory peptide**; result is slower stomach contraction; slower emptying into duod thru pyloric sphincter (slower chyme secretion); more time to properly digest - absorb nutrients


4. Cell determination begins At what stage of development
Homologous chromosomes line up w/ attachment of spindle fibers/microtubule polymers to centromeres via kinetochores; identical in appearance under light microscope to metaphase of mitosis
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine


5. Epithelium of the sm intestine: enterocytes lined w/brush border (digestion/absorption); goblet cells (mucous); crypts of Lieberkuhn exocrine glands (lysozyme)
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)
Inner lining of blood vessels
Liposome has phospholipid bilayer


6. components of interstitial fluid
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Glycosaminoglycans - prots - AAs - lipids


7. What controls release of LH - FSH from anterior pituitary
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Gonadotropin releasing hormone - GnRH
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Uncontracted: parasymp (eg opoid use)


8. Failure of apoptosis can result in
Lower blood pH
Cancer; apop can be programmed cell death; mitochon can play important role in apop
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
Night vision


9. In effect LH - FSH stimulate
Prod of steroid hormones in testes - ovaries
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue


10. What is somatostatin
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
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


11. serous membranes have a viscera - facing layer and a body wall - facing layer
Inner lining of blood vessels
Low because AAs are immediately used in translation
Meiosis creates germ cells
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity


12. sporic life cycle
Interstitial fluid (eg prostaglandins - cytokines)
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Direction of differentiation
Carry signals to musc OR Gland


13. Leydig cells produce
Zygote (fertilization in fallopian tubes); morula (up to 8 cells - undifferentiated ie totipotent); blastocyst (4+ days - implants into uterus; HCG secretion stims corpus luteum; gradually placenta replaces HCG as estrogen/progest source; cells not t
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Testosterone upon stim by LH
Epithelial tissue near semniferous tubules


14. Important aspect of crypt of Lieberkuhn - secreted intestinal juice
Liver Functions pt. 2 - Carb metabolism: blood is sent straight to liver from sm intest thru portal vein; liver is control center for blood glucose; _______________ - fat metabolism: oxidizes fat for energy by beta - oxidation - forms most lipoprotei
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity


15. bile + fat forms
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
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Paracrine (local) - endocrine (longer distance)


16. How is glucose absorbed in sm intest
In gastric pits; secretions combine into gastric juice
via symport - secondary transport (ie by pre - established - ATP- intensive) with Na gradient into enterocyte......with no Na gradient (ie without ATP) carbohydrate monomers could not be transported in
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)


17. portal vein physiology...

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18. Where are these exocrine glands located
Transfer signals from neuron - neuron; 90% of neurons are interneurons
In gastric pits; secretions combine into gastric juice
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Lower blood pH


19. Beta - oxidation in liver produces...
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)
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
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
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy


20. What is secreted into filtrate by cells of the proximal tubule?
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Glucose and ketone bodies (not from glycogen stores)


21. mucus cells line the stomach...
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Glucose
Contain rough ER and Golgi to make mucous; mucous is full of **glycoprots (sticky) and electrolytes*; protects epithelial tiss of stomach from low pH and lubricates stomach
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal


22. Ovum development is halted At what stage until fertilization...
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
ER
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete


23. Path of urine

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24. What is gastric acid?
***nicotinic is ionotropic; muscarinic is GPCR
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
HCl; secreted by parietal cells under stim by gastrin
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


25. energy source of neurons
Glucose and ketone bodies (not from glycogen stores)
Ganglion
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
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'


26. A pinpoint iris is contracted or uncontracted
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**
Processes: axons - dendrites
Uncontracted: parasymp (eg opoid use)
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy


27. Inside the kidney: ...JGA (w/granular cells sensitive to hydrostatic pressure able to secrete renin - activate aldosterone - increase BP) is adjacent to distal tubule - monitors filtrate pressure
Sorts - modifies - concentrates proteins from the ER
- 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
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss


28. What is main difference is signal transmission in nicotinic vs muscarinic?
***nicotinic is ionotropic; muscarinic is GPCR
Liver Functions pt. 2 - Carb metabolism: blood is sent straight to liver from sm intest thru portal vein; liver is control center for blood glucose; _______________ - fat metabolism: oxidizes fat for energy by beta - oxidation - forms most lipoprotei
Pancreatic duct (made of acinar cells?)
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals


29. 90% digestion - absorption occurs in...
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Determined by whether in front of or behind the lens
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


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

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31. Adrenal medulla hormones (TYR- DERIVED)
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
It targets liver conc of prothrombin - fibrinogen etc
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Has memb - bound organelles - etc...


32. What is the adventitia?
It targets liver conc of prothrombin - fibrinogen etc
Outermost layer of blood vessel
RBCs - large proteins; What does enter is called the filtrate
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct


33. Local vs long - distance mediators
Paracrine (local) - endocrine (longer distance)
Meiosis creates germ cells
5
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors


34. Kidney physiology...

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35. Anatomy of the villi
Contain capillary network - lymph vessels (lacteals)
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Gastrulation occurs: formation of three primary germ layers = differentiation


36. Polypeptides are formed with what kind of reaction?
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots


37. Examples of GPCRs in sensory systems/signal transduction: What is the ligand or messenger in each case? ...SIGHT - SMELL - MOOD - FIGHT/FLIGHT etc
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
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
Abdominal cavity - which is coated in serous fluid


38. Where do pancreatic secretions take effect
Break down TAGs to monoglycerides and free fatty acids
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
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc


39. examples of different cavities... (compartments for viscera)
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
***nicotinic is ionotropic; muscarinic is GPCR
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)


40. insulin secreted by
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Beta cells
Needs time for bile - lipase - micelle migration - enterocyte uptake


41. So - following blastocyst implantation (4d) - at approx 2 weeks past fertilization
Gastrulation occurs: formation of three primary germ layers = differentiation
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Chyme (by combined activity of exocrine glands)


42. PNS review: SAME DAVE
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Neurons may perform one of three functions....


43. going down the loop of Henle - water - permeable - filtrate osmolarity goes up as water leaves...
Testosterone upon stim by LH
Apoproteins attach to outside of globules; these move to Golgi and are released into interstitial fluid via exocytosis as chylomicrons --->most go to lacteal system
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges


44. zygotic life cycle
Digestion
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Systems (eg digestive system consists of many organs)


45. hypothalamus - AP - ACTH - cortisol release from adrenal cortex
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Liver Functions pt. 2 - Carb metabolism: blood is sent straight to liver from sm intest thru portal vein; liver is control center for blood glucose; _______________ - fat metabolism: oxidizes fat for energy by beta - oxidation - forms most lipoprotei
Below hypothalamus
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose


46. What is the function of the loop of Henle
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
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Prod of steroid hormones in testes - ovaries
Increases solute conc and osmotic pressure of the ***medulla


47. 3 phases of menstrual cycle
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
23 N; 23 chromosomes and haploid (no homologous chromosomes); each chromosome has two sister chromatids Male: primary spermatocyte -->REDUCTIONAL DIVISION (first stim'd at puberty by GnRH - LH-->secondary spermatocyte Female: primary oocyte (arreste
'The hepatic portal vein is not a true vein - because it does not conduct blood directly to the heart. It is a vessel in the abdominal cavity that drains blood from the gastrointestinal tract and spleen to capillary beds in the liver.'
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)


48. calcitonin

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49. sensory (afferent) neurons
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Liver Functions pt. 2 - Carb metabolism: blood is sent straight to liver from sm intest thru portal vein; liver is control center for blood glucose; _______________ - fat metabolism: oxidizes fat for energy by beta - oxidation - forms most lipoprotei
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
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide


50. when cells hit their limit for prot storage...
23 N; 23 chromosomes and haploid (no homologous chromosomes); each chromosome has two sister chromatids Male: primary spermatocyte -->REDUCTIONAL DIVISION (first stim'd at puberty by GnRH - LH-->secondary spermatocyte Female: primary oocyte (arreste
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
AAs can be burned for energy or converted to fat for storage
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases