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 Changes - Doesn't Change as a result of movement of molecules across membranes in the proximal tubule
Faces the lumen
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Digestion
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded


2. How does birth control work?
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Sorts - modifies - concentrates proteins from the ER


3. Some epithelial cells are... others...
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Determined by whether in front of or behind the lens
- 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
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide


4. What is the function of the loop of Henle
Increases solute conc and osmotic pressure of the ***medulla
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Fovea (highest amount of cones)
Nitrogen


5. So - following blastocyst implantation (4d) - at approx 2 weeks past fertilization
Night vision
It targets liver conc of prothrombin - fibrinogen etc
Gastrulation occurs: formation of three primary germ layers = differentiation
Buildup of macromolecules in lysosome due to deficient lysosome enzymes


6. bile + fat forms
Sorts - modifies - concentrates proteins from the ER
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Micelles; micelles transport lipase products to enterocytes for absorption at brush border


7. hypothalamus - AP - ACTH - cortisol release from adrenal cortex
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
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
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Nitrogen


8. After meiosis II - Male

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9. What controls release of LH - FSH from anterior pituitary
Interstitial fluid (eg prostaglandins - cytokines)
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Gonadotropin releasing hormone - GnRH


10. 90% digestion - absorption occurs in...
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
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
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion


11. spermatogonia arise from
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)
Pancreatic duct (made of acinar cells?)
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Epithelial tissue near semniferous tubules


12. oxytocin
Peripheral nervous sys
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Water flows from the tubule - concentrating the filtrate - raising BP
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion


13. lysosome main function and derivation
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)


14. Between meals most fats appear in blood as
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
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


15. from thoracic duct - chylomicrons stick to capillary walls...
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)


16. What is an endorphin?
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
An endogenous morphine
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Interstitial fluid (eg prostaglandins - cytokines)


17. At post - two weeks ovulation
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
Moves down thru esophageal sphincter
Corpus luteum degrades into corpus albicans
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation


18. Chewing does what?
Somatic nervous sys - autonomic nervous sys
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Increases surface area of food ball (bolus)


19. going down the loop of Henle - water - permeable - filtrate osmolarity goes up as water leaves...
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Direction of differentiation
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
Corpus luteum degrades into corpus albicans


20. almost all cells can store Some glycogen - but...
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)
Only musc and esp ** liver can store large amounts
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
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle


21. keep in mind that enterocyte is like a regular euk cell
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
Smooth ER
Has memb - bound organelles - etc...
Inner lining of circulatory system


22. The apical side of the villi...
All carbs absorbed at enterocytes are carried to liver by portal vein
Increases blood Calcium
The renal corpuscle
Faces the lumen


23. Where do pancreatic secretions take effect
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
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter


24. portal vein physiology...

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25. cAMP - cGMP - calmodulin...
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
Uncontracted: parasymp (eg opoid use)
Lumen (ie continuous w/body cavity) and cytosol
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)


26. What is the endothelium?
Most absorption occurs in sm intestine
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Creates one ovum (23 N) and three polar bodies
Inner lining of circulatory system


27. Determination is different than differentiation
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Systems (eg digestive system consists of many organs)
Processes: axons - dendrites
Increases solute conc and osmotic pressure of the ***medulla


28. trypsin is secreted by
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Determined by whether in front of or behind the lens
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Micelles; micelles (made of bile) go back and forth between brush border and chyme


29. Tight junctions
vitreous humor - retina - fovea
Inner lining of blood vessels
Form barrier to extracellular fluid
Estradiol


30. After meiosis I - daughter cells are...

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31. in the dark is rhodopsin active or inactive?
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
Liposome has phospholipid bilayer
Peptides
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching


32. What is a toxic byproduct of gluconeogenesis from proteins
Ammonia; must be converted to urea by liver and excreted in urine by kidney
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Contain capillary network - lymph vessels (lacteals)
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves


33. Glucose is a .... sugar; fructose is a .... sugar
Gonadotropin releasing hormone - GnRH
Gastrulation occurs: formation of three primary germ layers = differentiation
Glucose = aldose fructose = ketose
Transfer signals from neuron - neuron; 90% of neurons are interneurons


34. Blastocyst
Determined by whether in front of or behind the lens
- 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
Meiosis creates germ cells
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


35. Where does the bolus go after mouth chews food
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Below hypothalamus
Interstitial fluid (eg prostaglandins - cytokines)
Moves down thru esophageal sphincter


36. Beta - oxidation in liver produces...
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
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
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases


37. How does duod deal with hi HCl from stom
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Nitrogen
Ups bicarbonate secretion by pancreas; raises pH to 6.0
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


38. pancreatic enzymes are zymogens
HCl; secreted by parietal cells under stim by gastrin
Food is digested from mouth to stomach (denaturation by gastric acid - digested by pepsin) to duodenum (more digestion); then absorption occurs in jejunum and ileum
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
The renal corpuscle


39. Kidney physiology...

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40. Morula (...totipotent)
Testosterone and estradiol
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage


41. 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
Needs time for bile - lipase - micelle migration - enterocyte uptake
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Salivary amylase; both hydrolyze glycosidic linkages


42. Path of urine

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43. What are the memb - bound enzymes of the brush border?
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
The wall of the body or of a body cavity or hollow structure
Chyme (by combined activity of exocrine glands)
Abdominal cavity - which is coated in serous fluid


44. Meiosis I Metaphase I
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
Beta cells
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
RBCs - large proteins; What does enter is called the filtrate


45. testosterone can be aromatized to...
Two perpendicular semicircular canals involved in balance - equilibrium
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Estradiol


46. bundles of collecting ducts are called
Peptides
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Fructose is a structural isomer of glucose


47. Peritoneal refers to...
Abdominal cavity - which is coated in serous fluid
Lower blood pH
Oxytocin and ADH (aka vasopressin)
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. Stomach has no lacteals
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Most absorption occurs in sm intestine


49. axon hillock physiology
Mostly reabsorbed to liver
Conjunction of cell body w/axon
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
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage


50. peroxisome is derived from this
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
ER
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
Liposome has phospholipid bilayer