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1
Q

What makes up the endocrine system?

A

Glands

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2
Q

What are glands?

A

Glands produce, store, and secrete chemical molecules (hormones) that act as messengers.

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3
Q

What are hormones?

A

Hormones are secreted into the bloodstream and stimulate a physiological response further from point of origin.

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4
Q

Endocrine gland versus exocrine gland?

A

Endocrine gland
Always secrete into bloodstream
act far from point of origin

Exocrine gland
Secrete through ducts
example (sweat, mammary, digestive)

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5
Q

Autocrine versus Paracrine

A

Autocrine hormones act on the same cell that produces them (immune system)

Paracrine hormones act on organs or cells that are close by (hypothalamus on pituitary gland)

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6
Q

Hypothalamus in the endocrine system?

A

Main control center for the endocrine system.
Link the endocrine and nervous systems, and send signals to the pituitary gland that guides most of the endocrine glands.
It releases hormones that act on the pituitary to release another hormone that affects another gland.

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7
Q

What hormones does the hypothalamus produce (make)?

A

ADH (anti-diuretic hormone)
Oxytocin

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8
Q

What does ADH do?

A

ANTI-diuretic hormone means LESS production of urine
Less urine means an increase in blood volume

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9
Q

What does Oxytocin do?

A

Act during labor and delivery (cervical dilation, uterine contraction, milk release for the baby to feed)

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10
Q

What is the pituitary gland?

A

Produces all the other hormones in the endocrine gland.
It has two portions: anterior and posterior, hypothalamus acts on both

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11
Q

Thyroid gland function?

A

Produces two hormones called T3 (triiodothyronine) and T4 (thyroxine).

They both regulate metabolism.

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12
Q

Parathyroid gland function?

A

Have 4 small glands
Produces PTH (parathyroid hormone) and it regulates the body’s calcium level

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13
Q

Adrenal gland function?

A

Found on top of the kidneys
Divided into an outer cortex and inner medulla

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14
Q

What is the adrenal cortex’s function?

A

Make steroid hormones: mineralocorticoids, glucocorticoids, and androgens

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15
Q

What do mineralocorticoids do?

A

Help regulate electrolyte (salt) balance and hence fluid volume (for example aldosterone)

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16
Q

What do Glucocorticoids do?

A

They function in the regulation of metabolism and inflammation (for example cortisol;
aka cortex produces cortisol)

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17
Q

What do androgens do?

A

Sex hormones are produced in precursor forms and then converted by the gonads later on.

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18
Q

What is the adrenal medulla’s function?

A

The medulla produces catecholamines (adrenaline and noradrenaline or epinephrine and norepinephrine),
They play a role in your body’s fight-or-flight response.

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19
Q

What is the pancreas’ function?

A

The pancreas hormones help regulate blood sugar, through two hormones: insulin and glucagon.

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20
Q

What are the gonad’s functions?

A

in females, ovaries make estrogen and progesterone
in males, the testes make testosterone
These are important for secondary sexual characteristics.

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21
Q

How does the hypothalamus send signals to the anterior pituitary?

A

Through a network of capillaries, called the hypophyseal portal system (that is a paracrine system since glands are next to each other)

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22
Q

How does the hypothalamus communicate with the posterior pituitary?

A

Through nerves called the hypothalamic-hypophyseal tract.

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23
Q

GONADOTROPIN RELEASING HORMONE (GnRH)

A

GnRH released by the hypothalamus leads the anterior pituitary to release follicle-stimulating hormone and luteinizing hormone (FSH and LH). FSH and LH act on the gonads to release sex hormones.

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24
Q

CORTICOTROPIN RELEASING HORMONE (CRH)

A

CRH released by the hypothalamus leads the anterior pituitary to release adrenocorticotropic hormone (ACTH), which acts on the adrenal glands to release its hormones.

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25
Q

THYROTROPIN-RELEASING HORMONE (TRH)

A

TRH released by the hypothalamus leads the anterior pituitary to release thyroid stimulating hormone (TSH), which acts on the thyroid gland to release its hormones.

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26
Q

GROWTH HORMONE-RELEASING HORMONE (GHRH)

A

GH released by the hypothalamus leads the anterior pituitary to release growth hormone (GH), which acts on muscles and bones to stimulate growth.

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27
Q

PROLACTIN INHIBITORY FACTOR (PIF)

A

PIF is always released by the hypothalamus. When it stops being released, the anterior pituitary will start releasing prolactin, which is important for milk production in breastfeeding mothers.

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28
Q

What are the anterior pituitary hormones?

A

FSH, LH, ACTH, TSH, Prolactin, GH
The Mnemonic is FLAT PeG (e is for endorphins but not an hormone)

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29
Q

What are the posterior pituitary hormones?

A

It releases two hormones: ADH and oxytocin. These are made by the hypothalamus and stored in the pituitary until the release.

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30
Q

How are hormones controlled?

A

Same way as other chemicals: through metabolism (primarily through the liver) and excretion (through your kidneys, digestive system, or sweat)

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31
Q

NEGATIVE FEEDBACK in Hormones

A

A unique way that hormones are controlled. The effect of the hormone suppresses the release of more of that same hormone. For example, T3 and T4 act on receptors in the pituitary and hypothalamus to stop making TRH and TSH.

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32
Q

True or False: Autocrine hormones can act on both the cell that produces them as well as in parts of the body that are farther away.

A

False

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33
Q

Which gland is located in the brain and serves as a link between the endocrine system and the nervous system?a.Thyroidb.Pituitaryc.Hypothalamusd.Adrenal

A

Hypothalamus

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34
Q

Which gland produces hormones that direct the majority of endocrine glands in the body?a.Hypothalamusb.Pancreasc.Pituitaryd.Parathyroid

A

Pituitary

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35
Q

On which region of the pituitary gland does the hypothalamus act?a.Anteriorb.Posteriorc.Neither anterior nor posteriord.Both anterior and posterior

A

Both anterior and posterior

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36
Q

Which of the following statements is correct?a.GnRHleads to releaseof follicle-stimulating hormone and luteinizing hormone, which act on the gonads to release sex hormones.b.CRHleads to releaseofgrowth hormone, which acts on the adrenal glands to release its hormones.c.GHRHleads to releaseofadrenocorticotropic hormone,which acts on muscles and bones to stimulate growth.d.PIFis released by the hypothalamusas needed to stimulate release ofprolactin, which is important for milk production in breastfeeding mothers

A

GnRHleads to releaseof follicle-stimulating hormone and luteinizing hormone, which act on the gonads to release sex hormones

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37
Q

Which hormone regulates releaseofthyroid stimulating hormone, which acts on the thyroid gland to release its hormones?a.ACTHb.TRHc.FSHd.LHe.Prolactin

A

TRH

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38
Q

Which type of feedback loop does the body primarily utilize to regulate hormones within the endocrine system?a.Positive feedbackb.Negative feedback

A

Negative feedback

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39
Q

Based on information within the passage, what is likely a major function of AMH in the human body?a.AMH is a hormone released by an exocrine gland in order to regulate timing of estropause. b.AMH is a hormone that signals a woman’s transition to menopauseand altered capacity for ovulation.c.AMH is a hormone responsible for increasing a woman’s fertility, prolonging their childbearing years.d.AMH is an endocrine gland vital to the establishment of male and female sexual determination as well as a woman’s transition to menopause.

A

AMH is a hormone that signals a woman’s transition to menopause and altered capacity for ovulation.

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40
Q

4-vinylcyclohexene diepoxide (VCD) has been described as “a model chemical for ovotoxicity” because it causes selective destruction of ovarian follicles in rats by accelerating natural processes. What is a likely explanation for why this drug only impacts specific organs?a.This drug mimics a hormone, which recognizes specific receptors on certain cell types, meaning VCD does not act on every organ it encounters.b.This drug mimics a hormone released by the brain’s pituitary gland, the control center for the female endocrine system.c.VCD imitates the thyroid gland hormones, T3 and T4, which are known to target differentiated cells within reproductive organs.d.This drug mimics the pancreases’ function, which is mainly to regulate blood sugar levels but also to modulate progesterone release.

A

This drug mimics a hormone, which recognizes specific receptors on certain cell types, meaning VCD does not act on every organ it encounters.

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41
Q

What is another name for the gastrointestinal (GI

A

Alimentary canal (continuous with the space outside our body)
mouth–esophagus–

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42
Q

What happens in the mouth during ingestion?

A

Salivary glands (submandibular) secrete saliva that lubricates the food

4 types of salivary glands parotid, submandibular, sublingual, and von Ebner’s glands.

Then hydrolysis: Saliva digests macromolecules into smaller products

Salivary amylase: hydrolyze large starches into small disaccharide
Lingual lipase: break down large fat molecules ( triglycerides) into smaller free fatty acids and mono and diglycerides.

Chewing and hydrolysis combine the food into a bolus that is swallow

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43
Q

What is the epiglottis?

A

prevents the bolus from entering the trachea

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44
Q

What happens in the esophagus?

A

It lies behind the trachea, transports food to the stomach
Two muscles that help the food go in one direction: Top- the upper esophageal sphincter (UES); bottom: lower esophageal sphincter(LES) or cardiac sphincter.

UES- skeletal muscles, our control
LES- sits under the thoracic cavity, does not function as a sphincter, prevents reflux of acid into the stomach if loose causes heartburn.

3 parts: upper 1/3- skeletal muscle
middle 1/3- skeletal and smooth muscle
lower 1/3- smooth muscle

Bolus move through the esophagus by peristalsis (use hormonal and muscular systems)

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45
Q

What happens in the stomach?

A

J- shaped organ
Digest, process, and store food
3 functions digestion, regulating volume into the intestine, and combat against microorganisms.

3 parts:
Fundus: the upper area
Pylorus: exit the stomach to the intestine
Folding: inside to help increase surface area

Chum the bolus from the esophagus, hydrolyze the molecules for digestion, and create chyme to be processed into the small intestine.

Pyloric sphincter helps prevent reflux of chyme from 1st part of small intestine (duodenum), contract and prevent forward movement.

Duodenum prevent backward flow by secreting (CCK) cholecystokinin hormone from epithelial cells when it is full of chyme.

pH around 2 maintain by parietal cell (line the lumen)

Processing and digestion are now complete

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46
Q

What are parietal cells?

A

Parietal cell secrete HCl- destruct harmful microorganisms, hydrolysis reactions, conversion of hydrolytic enzymes.

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47
Q

What are Chief cells?

A

Chief cells secretes Pepsinogen
Pepsinogen convert to pepsin by HCl catalysis and breakdown protein into amino acids hat get absorb in the bloodstream.

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48
Q

What are mucous cells?

A

Mucous cells protect the stomach from self degradation. Produce mucin that counteract the acidic environment.

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49
Q

What are G cells?

A

G- cells secrete gastrin, hormone that coordinate activity of gastric acid HCl and pepsin secretion

Gastrin is release by presence of food or parasympathetic activity when resting and relaxing.

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50
Q

What happen in the Small intestine?

A

12 feet long
There are three distinct parts:
Duodenum,
Jejunum
Ileum.

Big surface area for digestion and absorption created by villi (hair-like projections in the walls of the small intestine) and microvilli (even smaller folding on each individual cell membrane)- known as the brush border.

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51
Q

What are villus?

A

hair-like projections in the walls of the small intestine.

Have defense system known as Peyer’s patches (lymphocytes that help secure the area from toxins and harmful microbes)

Contain lymphatic vessels know as lacteals- process and transport fat molecules to thoracic duct ending in blood vessels

Capillaries carry amino acid and disaccharides from broken down proteins and carbohydrates back to the venous systems which eventually connect to the hepatic vein that takes it to the liver for further processing.

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52
Q

What is the Duodenum function?

A

Two ducts empty into the duodenum
Common bile duct: delivers bile that help to digest fats (emulsification) & dispose unneeded element from liver. Bile is stored in the gallbladder.

Pancreatic duct: delivers digestive enzymes from the pancreas.

Bothe duct empty into one opening name Spinchter of Oddi

Secretes CCK that prevent forward movement of chyme, work on gallbladder to help empty bile to duodenum and pancreas to secrete digestive enzymes

Secrete secretin in response to high acidc environment that tell the pancreas to buffer the acid with sodium bicarbonate.

Pancreas enzymes need a slightly basic environment to function.

Also secretes enterogastrone that slow down stomach emptying in response to high contents in the duodenum.

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53
Q

What is the jejunum and ileum functions?

A

Allows for more digestion of carbohydrates, proteins, and fats.

The ileum absorbs vitamin B12 in combination with intrinsic factor which is secreted by parietal cells in the stomach.

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54
Q

What is the large intestine’s function?

A

A muscular tube that is wider and shorter than the small intestine.
Cecum then the appendix is composed of lymphatic tissue. It has 3 parts ascending, transverse, and descending colon.

It absorbs water and other nutrients to generate waste.

Anaerobic bacteria generate waste gas from undigested products. They also create vitamin K (blood clotting factor)

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55
Q

How is defecation controlled?

A

It is controlled by the internal and external sphincters. Internal uses smooth muscle (involuntary control) while external uses skeletal muscle (voluntary control)

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56
Q

What is the liver’s function?

A

Make bile; Move digested food to the hepatic portal venous system where the liver cell identifies the components.

Produce and secrete molecules related to immunity.

Produce proteins used for clotting such as albumin or fibrinogen (elevated clotting time in individuals with clotting disorders or liver disorders).

Liver creates waste products through urea (Ammonia is toxic so get converted through urea via the urea cycle).

Smooth ER in hepatocyte process toxins form various drugs help move to renal and GI system for excretion.

Process newly forms chylomicrons by small intestine, convert them to LDL and VLDL cholesterol hat goes in the blood for proteins to be added to cell recognition then go back to the liver to be HDL.

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57
Q

What is the gallbladder function?

A

Found at the bottom of the liver and stores the bile that the liver produces.

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58
Q

What is bile?

A

Made of of salts: bilirubin fom breakdown of red blood cells, cholesterol.

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59
Q

What is gallstone?

A

Form from excess cholesterol or bilirubin in the bile. This cause blockage of the bile duct (lead to pain in upper abdomen, nausea, vomiting)

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60
Q

What is the pancreas function?

A

Found in the center of the abdomen (epigastric region). It uses both the exocrine and endocrine system.

The exocrine glands secrete enzymes to help with digestion.

The endocrine glands secrete hormones in response to glucose levels (insulin and glucagon)

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61
Q

What is the pancreatic exocrine function?

A

Pancreatic amylase: Hydrolyzes polysaccharides to disaccharides
Pancreatic lipase: Hydrolyzes triglycerides into di- and mono- glyceride molecules.
Pancreatic proteases: Hydrolyzed polypeptides into tri- and di- peptides. Examples Trypsinogen to trypsin (via enterokinase) that activate Chym trypsinogen to chymotrypsin, Procarboxypeptidase to carboxypeptidase.

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62
Q

What is the pancreatic endocrine function?

A

That function is from the middle of the pancreas known as the Islets of Langerhans.
Alpha cells which secrete glucagon, beta cells which secrete insulin, as well as delta cells which secretes somatostatin.
Diabetes mellitus have two major types: I- autoimmune response; and II- developed later in life with an overuse of beta cells.

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63
Q

What hormones raise glucose levels?

A

Glucagon; epinephrine-secreted by the adrenal medulla; cortisol- secreted by the adrenal cortex. Last two secreted in stress repsonse.

Low blood glucose (known as hypoglycemia) can cause rhythm disturbances in the head.

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64
Q

Hormones for appetite regulation?

A

Increase (hungry)- ghrelin by gastric cells
Decrease (full belly)- leptin by adipose (fat tissue); Also done by peptide YY in the jejunum.

65
Q

Which enzyme helps break down large fatty molecules into triglycerides?
a.Lipase b.Amylase c.Carboxypeptidase d. Elastase

A

a.Lipase

66
Q

What is the normal pH of the stomach environment?
a.6.5 b.2 c.7.4 (physiologic pH) d. 9

A

b.2

67
Q

3) When it comes to the esophagus, the… is composed of … and is under our control.
a. LES; skeletal muscle b.UES; smooth muscle c. LES; smooth muscle d. UES; skeletal muscle

A

d. UES; skeletal muscle

68
Q

Which cell type in the stomach helps protect against self-degradation due to the HCl produced?
a.G cells b.Chief cells c.Mucous cells d. Parietal cells

A

c.Mucous cells

69
Q

What is the purpose of Peyer’s patches in the small intestine?
a. To coordinate’ movement of digested proteins and carbohydrates b. To secrete CCK to help with digestion c. To secure the area from harmful microbes and toxins. d. To process and transport fatty materials back to the thoracic duct.

A

c. To secure the area from harmful microbes and toxins.

70
Q

Which hormone is released in response to the acidic environment in the duodenum, and what does it help produce to buffer the environment?
a. Secretin; sodium benzoate b. Secretin; sodium bicarbonate c. Enterogastrone; sodium bicarbonate d. Cholecystokinin; hydrochloric acid

A

b. Secretin; sodium bicarbonate

71
Q

What is the function of the hormone CCK?
a. To help relax the pyloric sphincter and cause forward movement of chyme into the duodenum b. To contract the gallbladder in response to fatty foods c. A and B d. None of the above

A

b. To contract the gallbladder in response to fatty foods.

72
Q

The bacteria that exist in the large intestine help to ward off toxins and other pathogenic bacteria and also produce the clotting factor known as:
a. Vitamin D b. Vitamin C c. Vitamin A d. Vitamin K

A

d. Vitamin K

73
Q

Which combination of hormones can increase your blood glucose levels?
a. Glucagon, secretin. cortisol b. Epinephrine, glucagon, insulin c. Cortisol, glucagon, epinephrine d. Cortisol, epinephrine, gastrin

A

c. Cortisol, glucagon, epinephrine

74
Q

10) True or false? when your stomach is full, gastrin cells will produce the hormone ghrelin in order to stimulate an appetite.
a. True
b. False

A

b. False

75
Q

Based on the discussion between hormones and enzymes, which option make sense regarding their similarities/differences?a.Insulin is considered an enzyme because it speeds up reactions in order to convert glucose into glycogen to help control metabolism b.Insulin is considered a hormone because it easily diffuses through cell membranes to act on liver, muscle, and adipose cells c.Insulin is considered both an enzyme and a hormone because it is a peptide molecule d.Insulin is neither a hormone nor enzyme because it is made in the endocrine glands of the pancreas.

A

b. Insulin is considered a hormone because it easily diffuses through cell membranes to act on liver, muscle, and adipose cells.

76
Q

What is the reason for the acidic environment of the stomach? a.The acid environment is created to help inhibit microorganism production and functions as a defense mechanism for the body b.The acid environment is created to assist with the denaturation of proteins c.The acid environment is created to aid in the conversion of particular zymogens into their active form, such as trypsinogen to trypsin d.Both A and B e.All of the above

A

d. Both A and B

77
Q

Which combination of enzyme and their mechanism of action correlates with the information above?a.Pepsinogen, after conversion to its active form, will help to break down fatty acids into smaller fragments b.Sucrose helps convert carbohydrates into nucleic acid fragments in the small intestine c.Both salivary and pancreatic lipase function to break down triglyceride molecules into smaller monoglycerideand diglyceride molecules d.Enterokinase functions to convert chymotripsinogen to chymotrypsin in the exocrine glands of the pancreas

A

c.Both salivary and pancreatic lipase function to break down triglyceride molecules into smaller monoglyceride and diglyceride molecules

78
Q

What is bioenergetics??

A

The transfer of energy, or “thermodynamics in living organisms.

79
Q

What are the two main types of chemical reactions?

A

Endergonic –reactions that require energy (+ change of G)-non spontaneous
Exergonic –reactions that release energy (- change of G)- spontaneous

Endergonic reactions must be coupled to, and use the energy released from an exergonic reaction.

80
Q

What is free energy (G)?

A

Amount of energy a molecule contains.

81
Q

How is the change of G calculated?

A

CAN NOT be measured, only calculated
change G= change H - T (change S) or
subtracting the free energy in the substrates from the free energy in the products.
change G= G_products - G_substrates
Units= Joules/mol

82
Q

What is ATP?

A

Energy currency of the cell.
Exergonic reaction
The body thus uses the free energy generated by ATP hydrolysis to power its metabolic processes.

(3 phosphoryl group, adenosine (adenine ring and ribose sugar)

Reacts with water to form ADP.

83
Q

What does being in equilibrium means?

A

When the substrates and products have the same amount of free energy; zero change of free energy.

Only applied to a reversible reaction

84
Q

What is Le Chatelier’s principle?

A

Only applied to equilibrium and reversible reactions.

Increasing concentration in one substrate will decrease the other substrates.
shift reaction right.
Increase the concentration of all products

Pressure increase= reaction goes to the side of the reaction with the fewer number of moles of gas
Pressure decrease= reaction goes to the side of the reaction with the greater number of moles of gas

Adding heat= favor endothermic direction (seen on the reactant side)
shift reaction right.
decrease the number of other substrates.
Increase the amount of all products

85
Q

In an endergonic reaction, the products have ____ free energy than substrates because endergonic reactions ____ energy. a.more; require b.less; require c.more; release d.less; release

A

a. More, require.

86
Q

If you increase the concentration of a substrate of a reversible chemical reaction, when will the chemical reaction stop? a.Once the substrates are converted to products. b.Once the substrates are converted to products, and then back into substrates. c.Once equilibrium is reached.d.The reaction will never stop –reversible reactions are constantly occurring.

A

c.Once equilibrium is reached

87
Q

What three variables can you measure to calculate Gibbs free energy change? a.Change in heat, temperature, and change in entropy b. Change in heat, change in volume, and change in pressure c.ATP concentration, substrate-free energy levels, and product concentrations d.Change in heat, change in entropy and change in volume

A

a.Change in heat, temperature, and change in entropy

88
Q

If we could observe the molecules existing after ATP hydrolysis, what molecules would we expect to see? a.adenosine diphosphate b.adenosine diphosphate and an inorganic phosphate c.an inorganic phosphate and an adenosine d.two adenosines and an inorganic phosphate

A

b.adenosine diphosphate and an inorganic phosphate

89
Q

Where is the energy stored within an ATP molecule? a.within adenosine b.within the bond connecting adenosine and the first phosphoryl group c.within the phosphoryl groups d.within the bonds connecting the phosphoryl groups

A

d.within the bonds connecting the phosphoryl groups

90
Q

Creating a bonfire using logs, kindle, and paper is an analogy that can be used to describe what type of chemical reactions? a.Reversible b.Irreversible c.Coupling of endergonic and exergonic d.Both reversible and irreversible

A

b.Irreversible

91
Q

Based on the reaction below, what would you expect would happen to the concentration of “J” and “L” if you increased the concentration of “K”? L + P ⇌ J + K a.J would decrease, L would increase b.J would increase, L would decrease c.J and L would both increase d.J and L would both decrease

A

a.J would decrease, L would increase

92
Q

According to the passage, what is a reason why flavoproteins can be utilized in imaging techniques? a.Regular ATP hydrolysis is required for energy generation in living systems, therefore flavoprotein electron carriers can be exploited as a reliable detection method. b.Flavoprotein oxidation occurs within the mitochondrial electron transport chain; as mitochondria are a vital organelle in any cell type, this imaging technique allows for data collection in varied body system with high temporal accuracy. c.ATP hydrolysis is a bioenergetic process that occurs specifically in the cortexof the brain, making flavoproteins excellent targets for region-specific imaging in the brain. d.Similar to the oxygenation/deoxygenation cycle of hemoglobin, the ATP/ADP cycle can be exploited by imaging flavoproteins reduction in real-time.

A

a.Regular ATP hydrolysis is required for energy generation in living systems, therefore flavoprotein electron carriers can be exploited as a reliable detection method

93
Q

During optical imaging, it is reasonable to expect that ATP hydrolysis is coupled to which of the following? a.ATP hydrolysis is expected to be coupled to an exergonic reaction because hydrolysis utilizes the energy released. b.ATP hydrolysis is expected to be coupled to an endergonic reaction because hydrolysis releases energy for use in other reactions. c.ATP hydrolysis requires coupling; thus, hydrolysis is energetically unfavorable. d.ATP hydrolysis is not expected to be coupled to another reaction because it is itself an example of a spontaneous exergonic reaction.

A

ATP hydrolysis is expected to be coupled to an endergonic reaction because hydrolysis releases energy for use in other reactions.

94
Q

What are skeletal muscle functions?

A

Major metabolic organs
Important in thermoregulation (vasodilation when warm and vasoconstriction when cold)
Assist with peripheral circulation (use the heart) and help massage blood in the veins (bc. no smooth muscle, not a lot of pressure).

Stimulus: Voluntary
Appearance: Striated
Nucleation: Multi
Shape: Long- non branched
Location: Surrounding the body, attached to bones via tendons

95
Q

What is cardiac muscle function?

A

Stimulus: Involuntary
Appearance: Striated
Nucleation: Single/dual
Shape: Short- branched
Location: In the heart

96
Q

What is the smooth muscle function?

A

Stimulus: Involuntary
Appearance: Not striated
Nucleation: Single
Shape: Short, narrow/ tapered
Location: In the walls surrounding the hollow organs and vessels (GI tract, and circulatory vessels)

97
Q

What are the two types of control?

A

Voluntary and Involuntary.
Voluntary: Somatic motor neurons from peripheral nervous system branched to motor (efferent neurons) into the somatic nervous system (SNS)

Involuntary: Controlled by the motor (efferent) neurons, and by the autonomic nervous system (ANS)

98
Q

What are the two types of appearance?

A

Striated and non striated.
Striated contain sarcomeres found within 2 parallel z lines

Non striated have no sarcomeres arrangement

99
Q

What are the two types of nucleation?

A

Multinucleated and mononucleated
Multinucleated: contains multiple nuclei per muscle cell (muscle fiber)
Mononucleated: one nucleus _most somatic cells.

100
Q

What are the different shapes?

A

Skeletal muscles are long- unbranched (do not split)
Cardiac muscles are medium-length since they are more condensed- sometimes branched for cardiac contractions.
Smooth muscle looks like a typical cell tapered ends and a round middle portion

101
Q

What is the outer layer of the muscle called?

A

the epimysium: the protective layer of the muscle

102
Q

What is the middle layer called ?

A

the perimysium: covers/surrounds the multiple fascicles that exist in the muscle.

103
Q

What is the inner layer?

A

endomysium-coats each individual muscle cell

order muscle -multiple fascicles-multiple muscle fibers/cells

104
Q

What is a sarcomere?

A

Sarcolemma (membrane of the muscle)
Sarcoplasm (cytoplasm of the muscle)
sarcoplasm divided into multiple subunits: Myofibrils -contractile apparatus
Myofibrils contain Sarcomeres with boundaries called z lines
Sarcomeres are divided into Actin and Myosin
Actin: thin filament contains myosin binding site
Myosin: thick filament
I band ( only actin resides)
A - band ( only thick filament both actin and myosin) DO NOT CHANGE during contraction
H-band (house middle line only myosin resides there)

105
Q

What happens during muscular contraction?

A

Step 1 –Action Potential: opening of sodium at the alpha motor neuron opens calcium channels at the presynaptic neuron that lead to exocytosis of the vesicles (contains ACh) that bind to its receptor opening sodium on the muscle membrane (depolarizing) while calcium enters muscle cell.
Step 2 –T-tubule Propagation: Action potential travel down the t-tubule into the myofiber.
Step 3 –Ca2+Release at the Sarcoplasmic Reticulum (SR): extends into the myofiber; t-tubule attaches to SR through Ryanodine-Receptor that caused calcium to be released from SR which leads to muscle contraction.
Step 4 –Relaxation -Absence of Action Potential; Sarco/Endoplasmic Reticulum Ca2+-ATPase (SERCA) pump, pulls Ca2+ back into the SR. Then Acetylcholinesterase (AChE) metabolizes ACh and stops more action potentials.

106
Q

What happens during skeletal muscle contraction?

A

Tropomysion- block actin binding sites
Troponin associated with tropomyosin: 3 subunits C, I, T.
CA2 binds to troponin C, moving tropomyosin off the binding sites, and actin and myosin bind. When this occurs, myosin has ADP + P bound to it. Myosin bends toward SR, then release ADP +P leading to the Z lines shortening.

ATP attaches to myosin to have it released from actin then hydrolyzes. Energy stored in myosin head for next time.

107
Q

What does myosin look like?

A

Made up of a proteins chain (hexamer)
Two-heavy; contains the motor domain (1 in each); contains two binding sites: an ATP-binding site and an actin-binding site.
Four light: provide support and are considered regulatory

108
Q

What does actin look like?

A

made up of globular actin subunits (composed into a chain)
each contain a myosin binding site (active site)

109
Q

Muscle Innervation

A

The sympathetic branch contains pre-ganglionic neurons which utilize ACh, whereas the post-ganglionic neurons utilize the neurotransmitter noradrenaline/norepinephrine. The parasympathetic nervous system uses ACh as a neurotransmitter

110
Q

What are alpha motor neurons?

A

Lower Motor Neuron (LMN), which is found in the spinal cord-start or stop sending signals to the muscle
contains a cell body, termed the soma, which has dendrites that receive and process signals from the UMN( upper motor neuron)

111
Q

What is the node of Ranvier?

A

contains Na+channels which will allow the action potential to propagate the next node of Ranvier called saltatory conduction

112
Q

what is motor unit?

A

an alpha-motor neuron and all the muscle fibers it innervates
Motor unit = muscle fibers/ motor units

therefore same contractile unit and metabolic properties for each.

113
Q

What is a twitch contraction?

A

One stimulus, via the alpha-motor neuron, reaches the muscle and signals for it to contract
one contraction phase and one relaxation phase.

114
Q

What is a tetanic contraction?

A

before a muscle can relax from one twitch, there is another stimulation to contract, which will lead to there being more Ca2+ in the cytoplasm, which will then allow for actin and myosin to interact more. Continued stimuli at a high frequency causes the twitches to overlap.

115
Q

How else to increase muscle contraction?

A

to increase the number of motor units recruited

116
Q

What are the two types of fibers?

A

Slow twitch (Type I)
Fast twitch (Type II)
Myosin determines the fiber types
Human myosin heavy chain (MHC) exists in three isoforms: MHC-I, MHC-IIa, and MHC-IIx.
MHC-I : slowest to hydrolyzes ATP
MHC-IIa and IIx: Fast Twitch Muscle Fibers but IIx is the fastest.

Faster fiber have larger motor unit, more neural input

117
Q

What is size recruitment Principal?

A

more slow muscle at low intensities (lifting something light) and more fast muscle at
high intensities (lifting something heavy).

118
Q

Recently, a drug has been found to increase muscle specific intracellular calcium levels when motor units undergo “relaxation,” leading to prolonged muscular contraction. Which of the following could be a reason for the drug’s mechanism of action:
a.Partial agonist of muscarinic acetylcholinereceptors.
b.Blockage of the ryanodine receptors.
c.Prolonged opening of the SERCA pump.
d.Acetylcholinesterase inhibitor.

A

d.Acetylcholinesterase inhibitor.

119
Q

Which of the following statements is true?
a.Cardiac muscle is multi-nucleated.
b.Cardiac muscle contraction is voluntary.
c.Cardiac muscle is short and branched.
d.Cardiac muscle is not striated

A

c.Cardiac muscle is short and branched.

120
Q

Which of the following statements is true?
a.Skeletal muscle is mono-nucleated.
b.Skeletal muscle cells are short and branched.
c.Skeletal muscle contractions are involuntary.
d.Skeletal muscle sarcomeres are contained within myofibrils.

A

d.Skeletal muscle sarcomeres are contained within myofibrils.

121
Q

Which of the following is false?
a.Smooth muscle is found surrounding vesicles of the body.
b.Smooth muscle around blood vessels near the skin contract when we get cold.
c.Smooth muscle controls contraction in the veins to return blood to the heart.
d.Smooth muscle contractions are controlled by calcium.

A

c.Smooth muscle controls contraction in the veins to return blood to the heart.

122
Q

When a skeletal muscle contracts, which of the following does not occur?
a.Z-bands in a sarcomere pull further apart.
b.The M-line remains unchanged.
c.The A-Band remains unchanged.
d.The I-Band gets smaller.

A

a.Z-bands in a sarcomere pull further apart.

123
Q

Which of the following is the proper progression of muscle from large to small scale?
a.Gross muscle -muscle fibers -fascicles -myofibrils.
b.Gross muscle -fascicles -muscle fibers -myofibrils.
c.Gross muscle -myofibrils -muscle fibers -fascicles.
d.Gross muscle -myofibrils -fascicle -muscle fibers.

A

b.Gross muscle -fascicles -muscle fibers -myofibrils.

124
Q

After the action potential, mediated by Na+and K+, reaches the pre-synaptic terminal of the neuromuscular junction, which of the following occurs first?
a. Acetylcholine is released from pre-synaptic vesicles.
b.Pre-synaptic vessels go to the terminal of the axon and undergo exocytosis.
c.There is an influx of Ca2+ into the pre-synaptic terminal.
d.Acetylcholine binds to the acetylcholine receptor.

A

c.There is an influx of Ca2+ into the pre-synaptic terminal.

125
Q

Which of the following accurately describes the structure or function of the T-tubules?
a.They are required for the propagation of action potentials deep within the muscle fiber.
b.They received an action potential after the sarcoplasmic reticulum.
c.They store Ca2+ that is released to facilitate muscular contraction.
d.They contain ryanodine-receptors

A

a.They are required for the propagation of action potentials deep within the muscle fiber.

126
Q

Which of the following is true of the sarcomere?
a.The thin filament, actin, overlaps the thick filament, myosin, for a portion of the A-band.
b.The thick filament, actin, overlaps the thin filament, myosin, for a portion of the A-band.
c.The I-band contains myosin.
d.The thick filament is bound to the Z-band, and when muscle contracts, this is what pulls the Z-bands of a sarcomere together.

A

a.The thin filament, actin, overlaps the thick filament, myosin, for a portion of the A-band.

127
Q

Which is true of myosin?
a.It is made up of sixsubunits.
b.It has twomedium chains.
c.It interacts with tropomyosin.
d.It is a globular protein

A

a.It is made up of sixsubunits.

128
Q

Which does not happen during contraction?
a.Tropomyosin is removed from actin’s binding sites.
b.ATP is hydrolyzed to fuel the contraction.
c.Calcium binds to troponin-I.
d.The myosin stroke shifts to release ADP + P.

A

c.Calcium binds to troponin-I.

129
Q

Which of the following is true?
a.All muscle is innervated by the sympathetic nervous system.
b.Skeletal muscle is controlled by the somatic nervous system.
c.AChis the principal neurotransmitter for all muscle (skeletal, smooth, cardiac).
d.The brain stem controls skeletal muscle contraction.

A

b.Skeletal muscle is controlled by the somatic nervous system.

130
Q

Which of the following accurately describes a motor unit?
a.An alpha-motor neuron and all the muscle fibers it innervates.
b.An alpha-motor neuron and a single muscle fiber.
c.Muscle fibers that are innervated by an alpha-motor neuron with different fiber-types.
d.Muscle fibers in different muscles that are controlled by a single alpha-motor neuron.

A

a.An alpha-motor neuron and all the muscle fibers it innervates.

131
Q

What is true of the alpha-motor neuron?
a.It has a soma without dendrites.
b.They are short neurons.
c.They contain myelin that is produced by Schwann cells.
d.The nodes of Ranvier contain myelin

A

c.They contain myelin that is produced by Schwann cells.

132
Q

Which of the following is true about muscle contraction?
a.The contraction phase kinetics are determined only by the MHC-isoform.
b.A twitch is one stimulus followed by one contraction of a muscle fiber.
c.A tetanic contraction is due to multiple motor units being activated.
d.Force generation is only enhanced by increasing the frequency of motor unit activation.

A

b.A twitch is one stimulus followed by one contraction of a muscle fiber.

133
Q

True or False:If someone were to have an injury to one motor unit, it will prevent a whole muscle from contracting.
a.True
b.False

A

b.False

134
Q

Which of the following is false?
a.MHC-IIa and MHC-IIx fibers are also called fast twitch fibers.
b.MHC-IIxfibers are easier fibers to recruit.
c.MHC-I fibers appear more red because of mitochondria and myoglobin.
d.Contraction time is intermediate in MHC-IIa fibers.

A

b.MHC-IIxfibers are easier fibers to recruit.

135
Q

A drug that targets and breaks down acetylcholine esterase would do which of the following?
a.Prevent contraction
b.Prevent relaxation
c.Delay contraction
d.Delay relaxion

A

d.Delay relaxion

136
Q

Which of the following statements is false?
a.Skeletal muscle is multi-nucleated.
b.Skeletal muscle contraction is voluntary.
c.Myofibrils are short, repeated subunits in muscle.
d.Sarcomeres contain contractile proteins

A

c.Myofibrils are short, repeated subunits in muscle.

137
Q

A drug that prevents SERCA functioning would cause which of the following?
a.An increase in Ca2+reuptake by the SR.
b.A decrease in the contractile force of a myofiber.
c.An increase in contractile force of a myofiber.
d.Sustained muscle contraction.

A

d.Sustained muscle contraction.

138
Q

What are enantiomers?

A

L & D amino acids; are mirror-image molecules that cannot be superimposed on each other.

139
Q

What is zwitterion?

A

At neutral pH amino acids area dipolar ions
(NH2) is protonated (NH3+)
the carboxyl group (COOH) is deprotonated (COO-)
neutral in charge when at neutral pH.

140
Q

What happens at low pH?

A

amino acids exist in the cationic form in which only the amino group is protonated;

141
Q

What happens at high pH?

A

amino acids exist in the anionic form in which only the carboxyl group is deprotonated.

142
Q

Classification of Amino acids?

A

Hydrophobic: Non-polar R group
Hydrophilic: Polar R group
Basic: Positively charged R group
Acidic: Negatively charged R group
all acidic and basic amino acids are also hydrophilic.

143
Q

What are peptide bond?

A

linkage of aa through chemical bonds
they are amide bond
the electron pair on the amino group attacks the carboxyl carbon releasing water.

144
Q

What happens to cysteine

A

In an oxidizing environment, such as in the extracellular space, hydrogens of the thiol group (-SH Cysteine) are lost and a bond is formed between the two sulfurs(-S-S- cystine)

145
Q

What are the proteins level structure?

A

Primary: linear chain
Secondary: the result of hydrogen bonding between the polypeptide backbone(not the R groups)
Tertiary: 3D shape resulting from interactions between R groups of various amino acids which stabilize the structure.

Non-polar, hydrophobic amino acids generally cluster together at the center of the protein to reduce contact with the aqueous environment(this is known as hydrophobic bonding)
oPolar amino acids form hydrogen bonds
oCharged amino acids (acidic and basic) form ionic bonds
oCystines form disulfide bridges tofurther reinforce structure
oProlines are incapable ofparticipatingin hydrogen bonding and thus form the kinks and bends in a protein’s structure
Quaternary: two or more polypeptide chainsthat aggregate to form one functional macromolecule.

146
Q

What are the two protein techniques that we need for the MCAT?

A

isoelectric focusing and electrophoresis.

Isoelectric focusing: Separates charged molecules, such as proteins, based on their isoelectric point–the pH at which the protein has no charge.

Electrophoresis: denaturation with SDS, the electric field applied, and protein travel through the gel ( smaller protein travel faster) separation based on mass.

147
Q

In what way are acidic and polar amino acids similar?
a.They both are hydrophilic.
b.They both have a high isoelectric point.
c.They both are hydrophobic.
d.They are both involved in peptide bond formation.

A

a.They both are hydrophilic.

148
Q

Which of the following statements is true of zwitterions?
a.They are dipolar ions that exist most commonly at low pH.
b.They contain a protonated amino group, but not a deprotonated carboxyl group.
c.They are neutrally charged dipolar ions.
d.They contain a deprotonated carboxyl group and an acidic R group.

A

c.They are neutrally charged dipolar ions.

149
Q

Which level of protein structure involves cystines?
a.Primary
b.Secondary
c.Tertiary
d.Quaternary

A

c.Tertiary

150
Q

Denaturation through high temperature does not affect which level of protein structure?
a.Primary
b.Secondary
c.Tertiary
d.Quaternary

A

a.Primary

151
Q

Which of the following can be expected if a protein’s solvation layer is altered from an aqueous solvent to a nonpolar solvent?
a.Conformational stability will be maintained.
b.Folding will be altered as hydrophobic amino acids shift to the exterior of the protein structure.
c.Prolines will begin to form hydrogen bonds thus creating new alpha helices.
d.Beta pleated sheets will unfold resulting in a loss of quaternary structure.

A

b.Folding will be altered as hydrophobic amino acids shift to the exterior of the protein structure.

152
Q

Which is true of polypeptides commonly found in the human body?
a.All amino acids used to build the polypeptide contain a chiral carbon.
b.All amino acids used to build the polypeptide will be found in the L configuration with the α carbon on the right side.
c.All amino acid building block are linked together via disulfide bridges, which are a type of hydrolysis reaction.
d.All amino acids used to build the polypeptide will be found in the L configuration with the amino group on the left side.

A

d.All amino acids used to build the polypeptide will be found in the L configuration with the amino group on the left side.

153
Q

Which of the following accurately describes separation techniques for proteins?
a. Electrophoresis separates proteins in a mixture based on their mass and the speed at which they move through a gel.
b.The most common technique for protein separation relies on exploiting differences in 3D protein structure.
c.Isoelectric focusing separates proteins based on their charge.
d.Electrophoresis is a separation technique that utilizes pH to distinguish between proteins in a mixture.

A

a. Electrophoresis separates proteins in a mixture based on their mass and the speed at which they move through a gel.

154
Q

The researchers performed their experiments using Tris buffer, which has a pH range of 7-9. What is the likely reason for this?
a.A pH of 9 helps to promote changes in primary structure of proteins, the main property of proteins being analyzed in this experiment.
b.This pH range creates a solvation layer suitable for biological processes and thus minimizes protein denaturation throughout the experiment.
c.Cysteine disulfide bridges form at a lower rate as pH increases through exposure to Tris buffer.
d.Tris buffer is the standard buffer used to separate peptides after protein digest.

A

b.This pH range creates a solvation layer suitable for biological processes and thus minimizes protein denaturation throughout the experiment.

155
Q

Assuming the researcher’s experiments were performed at neutral pH, which of the following can be expected of the peptides used for PSM?
a.The amino acids comprising the peptides subjected to mass spectrometry for PSM are expected to be zwitterions.
b.The amino acids comprising the peptides subjected to mass spectrometry will be predominantly D configuration enantiomers.
c.The peptides subjected to mass spectrometry will exhibit equal proportions of N terminals that have both a free amino group as well asa free carboxyl group.
d.The peptides used for PSM will have been cleaved through hydrolysis in a non-specific manner.

A

a.The amino acids comprising the peptides subjected to mass spectrometry for PSM are expected to be zwitterions.

156
Q

What is a closed Circulatory System?

A

Blood is contained within the vessels s and travels in one direction alone and loops back to the heart, without backflow.

The heart has two circuits for blood circulation:

Circulation through the lungs and back to the heart, is called the pulmonary circuit or pulmonary circulation (like a private message on Facebook)

Circulation throughout the rest of the body and its organs and back to the heart, which is called the systemic circuit or systemic circulation (like a news feed post on Facebook)

The heart has an additional system that sustained it , the coronary circuit or coronary circulation

157
Q

What are the basic components of blood?

A

Hematocrit (contain erythrocytes)
Buffy coat: Leukocytes and platelets
Plasma : Contains water, proteins, salts, lipids, and glucose

158
Q

What is the structure of the Heart?

A

has four distinct “chamber”
paired atrium and ventricle on the right side and another pair on the left.
The right atrium receives deoxygenated blood from two major blood vessels: the inferior and superior vena cava.
*The deoxygenated blood then passes to right ventricle. From here via the pulmonary artery, the blood is sent for reoxygenation in the lungs (both left and right).
*The left atrium then receives the oxygen-rich blood via the pulmonary veins. From here the oxygenated blood passes to the left ventricle.
*Blood from the left ventricle is pumped to the rest of the body via the aorta, the largest artery in the body. This pattern of pumping blood is called double circulation

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