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 endothelium?
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Inner lining of blood vessels
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
1) by integral ion channels 2) transmitted by second messenger system


2. A contracted iris occurs with what kind of stimulation
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Sympathetic: dilates pupil (for night hunting)
Regulated by gastrointestinal horms
Glucose and ketone bodies (not from glycogen stores)


3. Four tissues
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Meiosis creates germ cells
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Which is why lactase - maltase - dextrinase - sucrase are on brush border


4. smooth ER main function
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**
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Oxytocin and ADH (aka vasopressin)
Testosterone upon stim by LH


5. review: parietals secrete intrinsic factor...
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Increases solute conc and osmotic pressure of the ***medulla
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
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate


6. liver and blood glucose...
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Peptides
- 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


7. 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
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)
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
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus


8. Kidney
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
Salivary amylase; both hydrolyze glycosidic linkages
***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
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation


9. Meiosis I Anaphase I
Gastrulation occurs: formation of three primary germ layers = differentiation
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Systems (eg digestive system consists of many organs)


10. at lo blood sugar...
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
Facilitated diffusion: no symport w/ secondary transport
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)


11. parathyroid hormones
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability


12. mucus cells line the stomach...
Glucose = aldose fructose = ketose
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
Organs
Direction of differentiation


13. ligands are the messenger compounds that target secondary messenger systems on effectors
Many modern drugs are ligands for GPCRs
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
Increases surface area of food ball (bolus)
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes


14. Mucus - digestive enzymes released thru
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Liposome has phospholipid bilayer
Glands w/ducts: Exocrine glands
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


15. What does peroxisome do
***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
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
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


16. Which fats are not absorbed like this
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
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
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins


17. How do nutrients move?
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
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Ups bicarbonate secretion by pancreas; raises pH to 6.0
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter


18. After meiosis II - Male

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19. components of interstitial fluid
Glycosaminoglycans - prots - AAs - lipids
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
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
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes


20. What testosterone released by secondary follicle by LH stim is converted to...
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
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
90-140 mg/dl


21. Important aspect of crypt of Lieberkuhn - secreted intestinal juice
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Primitive streak - which consists of cells of the MESODERM ****
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)
Form barrier to extracellular fluid


22. duodenum must have receptors for fat content - protein because
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
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
Lumen (ie continuous w/body cavity) and cytosol
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity


23. calcitonin

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24. Beta - oxidation in liver produces...
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Sympathetic: dilates pupil (for night hunting)
In mouth - breakdown of starch into polysaccharides
5


25. hypothalamus - AP - ACTH - cortisol release from adrenal cortex
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Form barrier to extracellular fluid


26. What do lipases do
Break down TAGs to monoglycerides and free fatty acids
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Alpha 1-4 and 1-6 (branching) glycosidic linkages
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


27. Where does the bolus go after mouth chews food
Ups bicarbonate secretion by pancreas; raises pH to 6.0
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
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Moves down thru esophageal sphincter


28. A group of cell bodies in CNS is nucleus - outside CNS is...
Carry signals to musc OR Gland
Salivary amylase; both hydrolyze glycosidic linkages
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
Ganglion


29. large intestine E. coli aid absorption of...
Carry signals to musc OR Gland
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Vitamin K - b12 - thiamin - riboflavin
Interstitial fluid (eg prostaglandins - cytokines)


30. light detection via GPCRs
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Primitive streak - which consists of cells of the MESODERM ****
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


31. Stomach has no lacteals
Many modern drugs are ligands for GPCRs
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
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)
Most absorption occurs in sm intestine


32. How does birth control work?
Somatic nervous sys - autonomic nervous sys
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
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


33. What is the pH at the entrance to the duodenum
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Membrane - bound - endocytosed bodies
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons


34. 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
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
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
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


35. Bile salts and lipase
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
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)
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
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct


36. A pinpoint iris is contracted or uncontracted
Interstitial fluid (eg prostaglandins - cytokines)
Uncontracted: parasymp (eg opoid use)
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Water flows from the tubule - concentrating the filtrate - raising BP


37. Kidney physiology...

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38. What is a normal blood glucose range
90-140 mg/dl
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
Fallopian tubes
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)


39. peroxisome is derived from this
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
ER
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron


40. Examples of GPCRs in sensory systems/signal transduction: What is the ligand or messenger in each case? ...SIGHT - SMELL - MOOD - FIGHT/FLIGHT etc
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
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
Normally contracted
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)


41. How does duod deal with hi HCl from stom
About 7.2
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Mostly reabsorbed to liver
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining


42. The path from blood plasma to urine

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43. In IBS - What is defective

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44. 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
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra


45. 80% of end product of carbohydrate metabolism is...
Fallopian tubes
AAs can be burned for energy or converted to fat for storage
Glucose
Homologous chromosomes separate - migrate towards opposite poles/centrioles


46. Three stages of the menstrual cycle
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Abdominal cavity - which is coated in serous fluid
Corpus luteum degrades into corpus albicans
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5


47. In general - parietal=
Nitrogen
The wall of the body or of a body cavity or hollow structure
Epithelial tissue near semniferous tubules
In gastric pits; secretions combine into gastric juice


48. week three: neurulation; mesoderm induces ectoderm; thus - NEURULATION INVOLVES SC Development - at week three
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
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
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)


49. What is the mesentery?
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective 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**
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane


50. overview of prot digestion
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
Epithelial tissue near semniferous tubules
Ammonia; must be converted to urea by liver and excreted in urine by kidney