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MCAT Prep - 2

Subjects : mcat, science

Instructions:

Answer 50 questions in 15 minutes.
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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. physiology of gall bladder - liver and pancreatic secretions
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
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

2. So - following blastocyst implantation (4d) - at approx 2 weeks past fertilization
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Gastrulation occurs: formation of three primary germ layers = differentiation
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)
Below hypothalamus

3. What is endothelium?
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
1) by integral ion channels 2) transmitted by second messenger system
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Inner lining of blood vessels

4. Determination is different than differentiation
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots

5. What Changes - Doesn't Change as a result of movement of molecules across membranes in the proximal tubule
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
Secondary oocyte (stim'd by LH stimulation of theca cells causing release of testosterone - converted to estradiol; eventually brings about luteal surge -->EQUATIONAL DIVISION-->ovum released during ovulation into fallopian tube; burst follicle becom
1) by integral ion channels 2) transmitted by second messenger system

6. Embryology
Sympathetic: dilates pupil (for night hunting)
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
In mouth - breakdown of starch into polysaccharides

7. Local vs long - distance mediators
Glucose
Paracrine (local) - endocrine (longer distance)
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate

8. calcitonin

9. Alpha - amylase found where
Organs
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
In mouth - breakdown of starch into polysaccharides
Liposome has phospholipid bilayer

10. liver and blood glucose...
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Liver is the control center for blood glucose; is fed by portal vein from sm intest
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons

11. In general - parietal=
Estradiol
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Most absorption occurs in sm intestine
The wall of the body or of a body cavity or hollow structure

12. 80-90% fat absorbed this way
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct

13. serous membranes have a viscera - facing layer and a body wall - facing layer
Neurons may perform one of three functions....
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Epithelial tissue near semniferous tubules
Buildup of macromolecules in lysosome due to deficient lysosome enzymes

14. What does peroxisome do
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
- 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
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
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

15. FLAT PG: FSH
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Secondary oocyte (stim'd by LH stimulation of theca cells causing release of testosterone - converted to estradiol; eventually brings about luteal surge -->EQUATIONAL DIVISION-->ovum released during ovulation into fallopian tube; burst follicle becom
Ventrally (picture skeletal vertebrae)

16. Where else does ADH act
Systems (eg digestive system consists of many organs)
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching

17. The path from blood plasma to urine

18. What is a toxic byproduct of gluconeogenesis from proteins
Ganglion
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals

19. what else is located in the inner ear (not directly related to auditory)
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Fallopian tubes
Two perpendicular semicircular canals involved in balance - equilibrium
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule

20. interneurons
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
Sensory (afferent - dorsal) - motor (efferent - ventral)
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
Transfer signals from neuron - neuron; 90% of neurons are interneurons

21. Anterior eye
1) by integral ion channels 2) transmitted by second messenger system
Beta cells
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor

22. Epithelium of the sm intestine: enterocytes lined w/brush border (digestion/absorption); goblet cells (mucous); crypts of Lieberkuhn exocrine glands (lysozyme)
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
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)

23. gradual increase in FSH typical of primary follicle development;
Night vision
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Increases surface area of food ball (bolus)
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

24. What is an endorphin?
Chyme (by combined activity of exocrine glands)
An endogenous morphine
Inner lining of blood vessels
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome

25. is intracellular AA conc hi or low?
Low because AAs are immediately used in translation
Nitrogen
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
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

26. Liver Functions
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
'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.'
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

27. Where would materials slated for digestion go?
Lysosome
Faces the lumen
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
- 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

28. What does lipase attack exactly
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
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
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

29. Thus - central nervous sys is...
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
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
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Glucose and ketone bodies (not from glycogen stores)

30. little by little chyme is squirted out thru pyloric sphincter
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
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
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Regulated by gastrointestinal horms

31. energy source of neurons
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Gastrulation occurs: formation of three primary germ layers = differentiation
Glucose and ketone bodies (not from glycogen stores)
RBCs - large proteins; What does enter is called the filtrate

32. Energy from fat - prot - gluc
Facilitated diffusion: no symport w/ secondary transport
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Digestion

33. peroxisome is derived from this
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Inner lining of circulatory system
ER
Sympathetic: dilates pupil (for night hunting)

34. what happens when glycogen stores are saturated and blood sugar remains high?
- 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
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)

35. motor (efferent) neurons --> VENTRAL
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
Oxytocin and ADH (aka vasopressin)
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Carry signals to musc OR Gland

36. In effect LH - FSH stimulate
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Prod of steroid hormones in testes - ovaries
ER

37. Four tissues
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
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
In mouth - breakdown of starch into polysaccharides
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

38. micelles vs liposomes
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)
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
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Liposome has phospholipid bilayer

39. testosterone can be aromatized to...
Below hypothalamus
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Estradiol

40. What is feces composed of...
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
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves

41. size of chylomicrons (fat + apoproteins) vs lipoproteins ('cholesterol')
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
Gastrulation occurs: formation of three primary germ layers = differentiation
Chylomicrons are much bigger
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase

42. How does blood sugar move into tissues?
Within the paravertebral ganglion - running parallel to spinal cord
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Facilitated diffusion from hi to lo conc
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

43. Failure of apoptosis can result in
The renal corpuscle
Cancer; apop can be programmed cell death; mitochon can play important role in apop
- 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
vitreous humor - retina - fovea

44. Where do absorbed fats go in the enterocyte
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
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Liposome has phospholipid bilayer
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs

45. How does the body mobilize fat stores
***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
An endogenous morphine
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Water flows from the tubule - concentrating the filtrate - raising BP

46. FLAT PG: TSH aka thyrotropin
Secondary oocyte (stim'd by LH stimulation of theca cells causing release of testosterone - converted to estradiol; eventually brings about luteal surge -->EQUATIONAL DIVISION-->ovum released during ovulation into fallopian tube; burst follicle becom
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
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Testosterone upon stim by LH

47. Where do pancreatic secretions take effect
It targets liver conc of prothrombin - fibrinogen etc
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
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
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter

48. FLAT PG: ACTH
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP

49. Gland: ovaries
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Meiosis creates germ cells
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy

50. Different tissues working together
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
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)
Organs
Sympathetic: dilates pupil (for night hunting)