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. 3 phases of menstrual cycle
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)
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
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum


2. What kind of cells make up epithel tiss of stom - then sm intest?
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
Peptides
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
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)


3. A pinpoint iris is contracted or uncontracted
Faces the lumen
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
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Uncontracted: parasymp (eg opoid use)


4. In general - parietal=
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
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
The wall of the body or of a body cavity or hollow structure


5. hypothalamus - AP - ACTH - cortisol release from adrenal cortex
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
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes


6. sensory (afferent)/interneurons/motor (efferent)
Neurons may perform one of three functions....
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Systems (eg digestive system consists of many organs)
Homologous chromosomes separate - migrate towards opposite poles/centrioles


7. The esophageal sphincter is...
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Normally contracted
In mouth - breakdown of starch into polysaccharides


8. Stomach has no lacteals
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
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Lumen (ie continuous w/body cavity) and cytosol
Most absorption occurs in sm intestine


9. Kidney physiology...

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10. 'Cell bodies of somatic motor neurons are located in....'
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Pancreatic duct (made of acinar cells?)
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)


11. What does lipase attack exactly
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Uncontracted: parasymp (eg opoid use)
Sorts - modifies - concentrates proteins from the ER


12. therefore - How does plasma leave capillary at the renal corpuscle

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13. What is a nerve? (PNS)
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
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
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Membrane - bound - endocytosed bodies


14. From that point...
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Organs
AAs enter bloodstream for uptake by all cells (esp liver). If intracellular prot conc is at max AAs can be converted to fats or glucose via gluconeogenesis. Byproduct of gluconeo is ammonia --->urea.


15. gradual increase in FSH typical of primary follicle development;
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
In gastric pits; secretions combine into gastric juice
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Lower blood pH


16. FSH - LH - HCG - inhibin are...
Peptides
Primitive streak - which consists of cells of the MESODERM ****
Chylomicrons are much bigger
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle


17. Mucus - digestive enzymes released thru
Glands w/ducts: Exocrine glands
All carbs absorbed at enterocytes are carried to liver by portal vein
90-140 mg/dl
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity


18. euk cell has two principal sides
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
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
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)
Lumen (ie continuous w/body cavity) and cytosol


19. micelles also pick up
Interstitial fluid (eg prostaglandins - cytokines)
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
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)


20. What does peptic refer to in general
Digestion
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on


21. 90% digestion - absorption occurs in...
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
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
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Micelles; micelles transport lipase products to enterocytes for absorption at brush border


22. After meiosis II...
Inner lining of circulatory system
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Regulated by gastrointestinal horms
Peptides


23. Important aspect of crypt of Lieberkuhn - secreted intestinal juice
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Homologous chromosomes separate - migrate towards opposite poles/centrioles
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
Carbohydrates are highly hydrated: one water mol per carbon mol - fats are anhydrous: contain more reduced carbons per unit mass - altogether fats contain 6X energy per unit mass


24. pancreas secretes enzymes via
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
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Pancreatic duct (made of acinar cells?)


25. what else is located in the inner ear (not directly related to auditory)
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
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
Two perpendicular semicircular canals involved in balance - equilibrium


26. zygotic life cycle
(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
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
An endogenous morphine


27. Glucose is a .... sugar; fructose is a .... sugar
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
Glucose = aldose fructose = ketose
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
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


28. Meiosis I Telophase I
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)


29. What surrounds the hydrophilic heads of the new TAGs
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
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Inner lining of blood vessels
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


30. FLAT PG: hGH aka somatotropin
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)
Ups bicarbonate secretion by pancreas; raises pH to 6.0
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
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


31. What do villli do
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Fructose is a structural isomer of glucose
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
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'


32. micelles vs liposomes
Facilitated diffusion: no symport w/ secondary transport
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
Liposome has phospholipid bilayer
Fallopian tubes


33. During ejaculation - sperm...

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34. How does glycogen compare to starch
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
HCl; secreted by parietal cells under stim by gastrin
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc


35. SYMP neurons originate in= PARA neurons originate in=
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Water flows from the tubule - concentrating the filtrate - raising BP
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
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest


36. What is secreted into filtrate by cells of the proximal tubule?
Water flows from the tubule - concentrating the filtrate - raising BP
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Outermost layer of blood vessel
Albumin increases osmolarity of blood; increases osmotic pressure


37. liver and blood glucose...
Abdominal cavity - which is coated in serous fluid
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis


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

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39. Does bile digest fat?
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete


40. FLAT PG: FSH
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Glucose = aldose fructose = ketose
Pancreatic duct (made of acinar cells?)
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


41. position of AP...
Creates one ovum (23 N) and three polar bodies
Thru tight junctions by favorable osmotic gradient
Below hypothalamus
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...


42. mitosis creates somatic cells
Meiosis creates germ cells
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Contain capillary network - lymph vessels (lacteals)


43. After meiosis II - Male

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44. from thoracic duct - chylomicrons stick to capillary walls...
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Form barrier to extracellular fluid


45. 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
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
Chyme (by combined activity of exocrine glands)
Glucose


46. What is an endorphin?
An endogenous morphine
Inner lining of blood vessels
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Corpus luteum degrades into corpus albicans


47. bundles of collecting ducts are called
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Interstitial fluid (eg prostaglandins - cytokines)
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane


48. PNS nerve signal
Lysosome
Normally contracted
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
Only musc and esp ** liver can store large amounts


49. Most important nutrients absorbed by large intestine
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)
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Vitamin K - b12 - thiamin - riboflavin


50. energy source of neurons
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
Glucose and ketone bodies (not from glycogen stores)
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
- 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