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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. FLAT PG: ACTH
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
- 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
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)

2. What is feces composed of...
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
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
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Buildup of macromolecules in lysosome due to deficient lysosome enzymes

3. parathyroid hormone
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
It targets liver conc of prothrombin - fibrinogen etc
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Increases blood Calcium

4. The EYE
Chyme (by combined activity of exocrine glands)
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors

5. What is a dorsal root ganglion?
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
All carbs absorbed at enterocytes are carried to liver by portal vein
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
Albumin increases osmolarity of blood; increases osmotic pressure

6. sensory (afferent)/interneurons/motor (efferent)
The wall of the body or of a body cavity or hollow structure
Neurons may perform one of three functions....
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
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae

7. Some epithelial cells are... others...
Nitrogen
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
- 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

8. liver receives blood from...
Mostly reabsorbed to liver
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Organs
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

9. alpha - amylase in the mouth digests what kind of bond
'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.'
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Somatic nervous sys - autonomic nervous sys
Direction of differentiation

10. components of interstitial fluid
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Needs time for bile - lipase - micelle migration - enterocyte uptake
Glycosaminoglycans - prots - AAs - lipids
Peptides

11. SYMP neurons originate in= PARA neurons originate in=
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
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
In gastric pits; secretions combine into gastric juice

12. How does glycogen compare to starch
Lumen (ie continuous w/body cavity) and cytosol
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
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
Chyme (by combined activity of exocrine glands)

13. Where is bile produced
It targets liver conc of prothrombin - fibrinogen etc
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
Many modern drugs are ligands for GPCRs
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**

14. How is the follicle developed during oogenesis
Creates one ovum (23 N) and three polar bodies
Prod of steroid hormones in testes - ovaries
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Buildup of macromolecules in lysosome due to deficient lysosome enzymes

15. what cannot cross the fenestrations of the renal corpuscle
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
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
RBCs - large proteins; What does enter is called the filtrate
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots

16. What is secreted into filtrate by cells of the proximal tubule?
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
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics

17. For focal point that is nearby - what will the lens look like
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
- 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
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle

18. insulin secreted by
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
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Beta cells
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability

19. Where are these exocrine glands located
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Interstitial fluid (eg prostaglandins - cytokines)
In gastric pits; secretions combine into gastric juice
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'

20. important because in meiosis germ - line cells begin as 46 2N w/ 23 pairs of homologous chromosomes which are replicated in S phase of interphase to 23 pairs of sister chromatids = still 46 2N
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Interstitial fluid (eg prostaglandins - cytokines)
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
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

21. Both divisions (somatic - autonomic) of PNS consist of...
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Sensory (afferent - dorsal) - motor (efferent - ventral)
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
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)

22. Where do absorbed fats go in the enterocyte
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
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

23. what else is located in the inner ear (not directly related to auditory)
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
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
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Two perpendicular semicircular canals involved in balance - equilibrium

24. A contracted iris occurs with what kind of stimulation
Sympathetic: dilates pupil (for night hunting)
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
Outermost layer of blood vessel
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)

25. chylomicron concentration in blood after meal
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Monitors filtrate pressure in the distal tubule; has specialized cells (granular cells) that secrete an enzyme (**renin); renin initiates regulatory cascade that produces angiotensin I - II - III that stim adrenal cortex to secrete aldosterone... ...
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes

26. Gland: ovaries
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy

27. Sensory - motor neurons are part of which nervous system
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Lysosome
Peripheral nervous sys

28. In IBS - What is defective

29. During ejaculation - sperm...

30. Thus - central nervous sys is...
***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
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
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

31. FSH - LH - HCG - inhibin are...
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Peptides

32. What does peptic refer to in general
Digestion
It targets liver conc of prothrombin - fibrinogen etc
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
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome

33. From that point...
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
Oxytocin and ADH (aka vasopressin)
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.
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc

34. liver and blood glucose...
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)

35. peroxisome is derived from this
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
ER
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
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

36. at lo blood sugar...
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
***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
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Interstitial fluid (eg prostaglandins - cytokines)

37. motor (efferent) neurons --> VENTRAL
Carry signals to musc OR Gland
Outermost layer of blood vessel
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest

38. PNS review: SAME DAVE
Lysosome
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Direction of differentiation
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector

39. What is somatostatin
Sorts - modifies - concentrates proteins from the ER
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Oxytocin and ADH (aka vasopressin)
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5

40. Contrast PNS- Somatic with PNS- Autonomic
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
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.
Chyme (by combined activity of exocrine glands)

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

42. Meiosis I Anaphase I
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals

43. Alpha - amylase found where
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Faces the lumen
In mouth - breakdown of starch into polysaccharides
Zygotes are diploid

44. in the dark is rhodopsin active or inactive?
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
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
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
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection

45. main point of fat transport...
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane

46. Most important nutrients absorbed by large intestine
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Peptides
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs

47. interneurons
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Increases surface area of food ball (bolus)
Testosterone and estradiol
Only musc and esp ** liver can store large amounts

48. Three stages of the menstrual cycle
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
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

49. What is the mesentery?
Increases surface area of food ball (bolus)
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Lumen (ie continuous w/body cavity) and cytosol
Conjunction of cell body w/axon

50. bundles of collecting ducts are called
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Only musc and esp ** liver can store large amounts
'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.'