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 is the path of a sound wave that enters the ear?
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
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
It targets liver conc of prothrombin - fibrinogen etc
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy


2. hypothalamus - AP - ACTH - cortisol release from adrenal cortex
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
In mouth - breakdown of starch into polysaccharides
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose


3. What is an endorphin?
Prod of steroid hormones in testes - ovaries
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
An endogenous morphine
Micelles; micelles (made of bile) go back and forth between brush border and chyme


4. Kidney physiology...

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

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6. liver receives blood from...
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
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Digestion
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate


7. What is gastric acid?
Peptides
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
HCl; secreted by parietal cells under stim by gastrin
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)


8. What surrounds the hydrophilic heads of the new TAGs
Below hypothalamus
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
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
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)


9. Glycogenolysis/gluconeogenesis
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
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
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)


10. portal vein physiology...

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11. lysosome pH
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
5


12. lysosome main function and derivation
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Ventrally (picture skeletal vertebrae)
Glucose
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**


13. What if large intestine isn't working well
Sorts - modifies - concentrates proteins from the ER
Chylomicrons are much bigger
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
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


14. Luteal surge
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)


15. PNS nerve signal
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
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
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Systems (eg digestive system consists of many organs)


16. calcitonin

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17. Morula (...totipotent)
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
***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
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Fructose is a structural isomer of glucose


18. Ovum development is halted At what stage until fertilization...
Gastrulation occurs: formation of three primary germ layers = differentiation
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
The wall of the body or of a body cavity or hollow structure
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete


19. spermatogonia arise from
Form barrier to extracellular fluid
Low because AAs are immediately used in translation
Epithelial tissue near semniferous tubules
RBCs - large proteins; What does enter is called the filtrate


20. insulin secreted by
- 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
Beta cells
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
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


21. peroxisome is derived from this
ER
Fructose is a structural isomer of glucose
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)
Oxytocin and ADH (aka vasopressin)


22. Interaction of corpus luteum/placenta
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Neurons may perform one of three functions....
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
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


23. axon hillock physiology
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Conjunction of cell body w/axon
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
90-140 mg/dl


24. almost all exocytosed proteins pass through this
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Smooth ER
Glucose and ketone bodies (not from glycogen stores)
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid


25. fructose enters enterocyte by
Facilitated diffusion: no symport w/ secondary transport
Processes: axons - dendrites
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Form barrier to extracellular fluid


26. gametes are haploid
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Zygotes are diploid
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


27. Aldosterone (sodium uptake - potassium secretion)
Inner lining of circulatory system
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)
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**
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


28. when cells hit their limit for prot storage...
In gastric pits; secretions combine into gastric juice
AAs can be burned for energy or converted to fat for storage
Membrane - bound - endocytosed bodies
Beta cells


29. What force is acting upon chyme to move it forward down sm intestine
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Direction of differentiation
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera


30. In other words...
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
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Inner lining of circulatory system


31. Most important nutrients absorbed by large intestine
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Facilitated diffusion from hi to lo conc


32. Thus inhibiting parietal cells could do What to blood pH
Lower blood pH
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
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
HCl; secreted by parietal cells under stim by gastrin


33. light detection via GPCRs
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Prod of steroid hormones in testes - ovaries
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


34. remaining secondary follicle becomes
Primitive streak - which consists of cells of the MESODERM ****
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)


35. How does reabsorption force nutrients across apical membrane of proximal tubule
'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
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity


36. Determination is different than differentiation
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors


37. cytosol pH
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
About 7.2
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
Glucose = aldose fructose = ketose


38. Embryology
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
Conjunction of cell body w/axon
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
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy


39. Seen in lysosomal storage diseases
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
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


40. Embryology
Glucose
Needs time for bile - lipase - micelle migration - enterocyte uptake
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...


41. What does lipase attack exactly
Neurons may perform one of three functions....
'Microvilli function as the **primary surface of nutrient absorption in the gastrointestinal tract**. Because of this vital function - the microvillar membrane is packed with enzymes that aid in the breakdown of complex nutrients into simpler compoun
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation


42. The path from blood plasma to urine

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43. testosterone can be aromatized to...
Estradiol
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Contain capillary network - lymph vessels (lacteals)


44. main point of fat transport...
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons


45. Where do absorbed fats go in the enterocyte
Glucose
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue


46. How do monoglycerides and ffas get to brush border?
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Increases surface area of food ball (bolus)
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH


47. Chewing does what?
Increases surface area of food ball (bolus)
Ventrally (picture skeletal vertebrae)
Normally contracted
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch


48. almost all cells can store Some glycogen - but...
Epithelial tissue near semniferous tubules
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Only musc and esp ** liver can store large amounts
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching


49. Tight junctions
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Form barrier to extracellular fluid
Processes: axons - dendrites


50. little by little chyme is squirted out thru pyloric sphincter
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
Regulated by gastrointestinal horms
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Glands w/ducts: Exocrine glands