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MCAT Prep - 2

Subjects : mcat, science

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. inhibin secreted by
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
All carbs absorbed at enterocytes are carried to liver by portal vein
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production

2. examples of different cavities... (compartments for viscera)
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Prod of steroid hormones in testes - ovaries
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle

3. E storage per unit mass
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
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
Thru tight junctions by favorable osmotic gradient

4. portal vein physiology...

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5. important pancreatic enzymes
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
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

6. Stomach has no lacteals
Smooth ER
***nicotinic is ionotropic; muscarinic is GPCR
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Most absorption occurs in sm intestine

7. Kidney
Inner lining of blood vessels
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
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Determined by whether in front of or behind the lens

8. from thoracic duct - chylomicrons stick to capillary walls...
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
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**
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching

9. bundles of collecting ducts are called
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
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

10. Failure of apoptosis can result in
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Somatic nervous sys - autonomic nervous sys

11. What do the glomerulus and Bowman's capsule add up to...
Eukaryotes
Two perpendicular semicircular canals involved in balance - equilibrium
The renal corpuscle
Ganglion

12. trypsin is secreted by
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Prod of steroid hormones in testes - ovaries
Peripheral nervous sys

13. Contrast PNS- Somatic with PNS- Autonomic
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
In gastric pits; secretions combine into gastric juice

14. small intestine=
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)
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Smooth ER
Thru tight junctions by favorable osmotic gradient

15. Kidney physiology...

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16. What does peptic refer to in general
Digestion
vitreous humor - retina - fovea
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
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra

17. peroxisome is derived from this
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
ER
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
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

18. SYMP neurons originate in= PARA neurons originate in=
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
- 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
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

19. PNS is broken down into
- 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
Digestion
Somatic nervous sys - autonomic nervous sys
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...

20. from the loop of henle...
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**
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Abdominal cavity - which is coated in serous fluid

21. remaining secondary follicle becomes
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
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
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
RBCs - large proteins; What does enter is called the filtrate

22. sensory (afferent) neurons
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded

23. in mammals - gastrulation involves formation of the
1) by integral ion channels 2) transmitted by second messenger system
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Primitive streak - which consists of cells of the MESODERM ****
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons

24. What determines number of chromosomes?
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
90-140 mg/dl
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)

25. What is endothelium?
'Increased absorptive area is useful because digested nutrients (including sugars and amino acids) pass into the villi through diffusion - which is effective only at short distances. In other words - **increased surface area (in contact with the flui
Inner lining of blood vessels
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
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded

26. Different tissues working together
Organs
***nicotinic is ionotropic; muscarinic is GPCR
Interstitial fluid (eg prostaglandins - cytokines)
Only musc and esp ** liver can store large amounts

27. After meiosis II...
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
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
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

28. STOMACH: no absorption
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
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
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
Abdominal cavity - which is coated in serous fluid

29. What is the pH at the entrance to the duodenum
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
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH

30. FLAT PG: LH
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
***nicotinic is ionotropic; muscarinic is GPCR
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on

31. Important aspect of crypt of Lieberkuhn - secreted intestinal juice
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
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
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity

32. FLAT PG: prolactin
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)
Ganglion
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule

33. fructose enters enterocyte by
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
The renal corpuscle
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
Facilitated diffusion: no symport w/ secondary transport

34. Ovum development is halted At what stage until fertilization...
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
vitreous humor - retina - fovea

35. food in duod stims release of gastrointestinal hormones
All carbs absorbed at enterocytes are carried to liver by portal vein
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Two perpendicular semicircular canals involved in balance - equilibrium
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)

36. What happens when rod cell is depolarized
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
Moves down thru esophageal sphincter
Night vision
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)

37. What else do parietals do?
Contain capillary network - lymph vessels (lacteals)
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
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest

38. How does the body mobilize fat stores
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
***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
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
5

39. Chewing does what?
Abdominal cavity - which is coated in serous fluid
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Increases surface area of food ball (bolus)
Below hypothalamus

40. Epithelium of the sm intestine: enterocytes lined w/brush border (digestion/absorption); goblet cells (mucous); crypts of Lieberkuhn exocrine glands (lysozyme)
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Moves down thru esophageal sphincter
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger

41. What is the net effect of the loop of Henle
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
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
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)
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP

42. How does reabsorption force nutrients across apical membrane of proximal tubule
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
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

43. Gastrulation: ectoderm/mesoderm/endoderm
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Needs time for bile - lipase - micelle migration - enterocyte uptake
HCl; secreted by parietal cells under stim by gastrin

44. components of interstitial fluid
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
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Carry signals to musc OR Gland
Glycosaminoglycans - prots - AAs - lipids

45. PNS review: SAME DAVE
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector

46. Path of urine

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47. when cells hit their limit for prot storage...
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
AAs can be burned for energy or converted to fat for storage
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Transfer signals from neuron - neuron; 90% of neurons are interneurons

48. Tight junctions
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
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
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
Form barrier to extracellular fluid

49. Thus inhibiting parietal cells could do What to blood pH
Glucose and ketone bodies (not from glycogen stores)
Ganglion
Lower blood pH
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete

50. Three stages of the menstrual cycle
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
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
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