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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. So - following blastocyst implantation (4d) - at approx 2 weeks past fertilization
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Pancreatic duct (made of acinar cells?)
(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

2. What surrounds the hydrophilic heads of the new TAGs
Lumen (ie continuous w/body cavity) and cytosol
Break down TAGs to monoglycerides and free fatty acids
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
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)

3. AP- peptides (FSH - LH - ACTH - TSH - prolactin - hGH); PP- peptides (ADH - oxytocin); thyroid - peptide *and* tyr - derived (T3/T4 - calcitonin); parathyroid - peptide (PTH; raise blood Ca via pathway involving vitamin D)
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
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
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Eukaryotes

4. food in duod stims release of gastrointestinal hormones
Creates one ovum (23 N) and three polar bodies
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
'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

5. Glycogenolysis/gluconeogenesis
It targets liver conc of prothrombin - fibrinogen etc
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
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
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle

6. Aldosterone (sodium uptake - potassium secretion)
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
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)
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
An endogenous morphine

7. insulin secreted by
1) by integral ion channels 2) transmitted by second messenger system
Beta cells
- 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
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics

8. peroxisome is derived from this
Creates one ovum (23 N) and three polar bodies
ER
Uncontracted: parasymp (eg opoid use)
Faces the lumen

9. How does duod deal with hi HCl from stom
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus

10. What is secreted into filtrate by cells of the proximal tubule?
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes

11. small intestine=
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
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

12. What do lipases do
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Break down TAGs to monoglycerides and free fatty acids
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
'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

13. What is a toxic byproduct of gluconeogenesis from proteins
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
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

14. interneurons
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
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
Prod of steroid hormones in testes - ovaries

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

16. Think of spinal cord injury
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch

17. what happens to bile secretions
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Mostly reabsorbed to liver

18. A pinpoint iris is contracted or uncontracted
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Uncontracted: parasymp (eg opoid use)
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
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

19. What testosterone released by secondary follicle by LH stim is converted to...
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Night vision
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide

20. Chewing does what?
Increases surface area of food ball (bolus)
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
Fovea (highest amount of cones)
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

21. Meiosis II: EQUATIONAL DIVISION
Prod of steroid hormones in testes - ovaries
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
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Facilitated diffusion from hi to lo conc

22. What if large intestine isn't working well
Night vision
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Gonadotropin releasing hormone - GnRH
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals

23. In general - parietal=
Neurons may perform one of three functions....
It targets liver conc of prothrombin - fibrinogen etc
The wall of the body or of a body cavity or hollow structure
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons

24. what else is located in the inner ear (not directly related to auditory)
An endogenous morphine
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
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Two perpendicular semicircular canals involved in balance - equilibrium

25. Path of urine

26. mucus cells line the stomach...
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
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
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy

27. lining of abdominal cavity=
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Most absorption occurs in sm intestine

28. when thinking of proteins - think
Conjunction of cell body w/axon
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
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
Nitrogen

29. physiology of gall bladder - liver and pancreatic secretions
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
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
Fructose is a structural isomer of glucose
Normally contracted

30. PNS nerve signal
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
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
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
Faces the lumen

31. Sensory - motor neurons are part of which nervous system
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
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
Digestion
Peripheral nervous sys

32. ligands are the messenger compounds that target secondary messenger systems on effectors
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Conjunction of cell body w/axon
Many modern drugs are ligands for GPCRs
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

33. what happens when glycogen stores are saturated and blood sugar remains high?
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Zygotes are diploid

34. In other words...
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Glucose and ketone bodies (not from glycogen stores)
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
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

35. How long are peptides when absorbed at brush border
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)
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
***nicotinic is ionotropic; muscarinic is GPCR
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

36. Does bile digest fat?
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Somatic nervous sys - autonomic nervous sys
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase

37. only monosaccharides are absorbed
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
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
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)

38. Liver Functions
- 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
Primitive streak - which consists of cells of the MESODERM ****
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
Estradiol

39. Where does the bolus go after mouth chews food
Digestion
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Moves down thru esophageal sphincter

40. signal transduction occurs only in
Peptides
Eukaryotes
An endogenous morphine
Buildup of macromolecules in lysosome due to deficient lysosome enzymes

41. Where is bile produced
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
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**
Lumen (ie continuous w/body cavity) and cytosol
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries

42. Inside the kidney: ...JGA (w/granular cells sensitive to hydrostatic pressure able to secrete renin - activate aldosterone - increase BP) is adjacent to distal tubule - monitors filtrate pressure
Pancreatic duct (made of acinar cells?)
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
- 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
Inner lining of blood vessels

43. How does blood sugar move into tissues?
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Facilitated diffusion from hi to lo conc
Increases surface area of food ball (bolus)
Cancer; apop can be programmed cell death; mitochon can play important role in apop

44. From that point...
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
AAs enter bloodstream for uptake by all cells (esp liver). If intracellular prot conc is at max AAs can be converted to fats or glucose via gluconeogenesis. Byproduct of gluconeo is ammonia --->urea.
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen

45. Kidney physiology...

46. portal vein physiology...

47. bundles of collecting ducts are called
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
'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

48. Examples of GPCRs in sensory systems/signal transduction: What is the ligand or messenger in each case? ...SIGHT - SMELL - MOOD - FIGHT/FLIGHT etc
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
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
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

49. What Changes - Doesn't Change as a result of movement of molecules across membranes in the proximal tubule
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
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
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
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane

50. exocrine types
ER
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)
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal