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Human Physiology > Exam 4 LO > Flashcards

Exam 4 LO Flashcards

1
Q

Major roles of saliva

A

Starch breakdown
Food solubilization
Protection
Absorption
Lubrication

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2
Q

Major digestive enzyme present in the saliva, responsible for starch breakdown

A

alpha amylase

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3
Q

Alpha amylase’s ability to function depends on…

A

how well food is chewed

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4
Q

Starch breakdown is important in the mouth because…

A

amylase is deactivated in the stomach due to acidic environment

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5
Q

Breaking down food releases chemicals that activate…

A

taste receptors in mouth, if something doesn’t get broken down then you cannot taste it as well

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6
Q

In food solubilization, dissolved chemicals diffuse into…

A

pores in tongue, sensed by taste hairs that depolarize the membrane—activating NS

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7
Q

Protects against chewing of sharp material

A

Mucins producing thick mucus

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8
Q

pH of saliva and it’s role

A

Alkaline pH buffers against acidic foods and stomach acid

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9
Q

Absorption of what molecules can occur directly in the mouth? What happens when molecules are absorbed directly in the mouth?

A

Low molecular weight. they bypass (bypass hepatic portal vein) the first round of liver metabolism and go straight into the bloodstream

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10
Q

What do mucins produce and how it is relevant for lubrication?

A

glycoproteins that coat the food so you can move it around and important for swallowing

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11
Q

Swallowing is what kind of reflex

A

Long reflex

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12
Q

Explain the voluntary phase of swallowing

A

Tongue pushes food bolus back and upward’s towards the back of the mouth, once food touches the soft palate and back of mouth which triggers swallowing reflex

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13
Q

Explain the pharyngeal phase of swallowing

A

Medulla initiates swallowing reflex, causing soft palate to elevate, closing the glottis and opening the esophageal sphincter (once food moves into esophagus and sphincter closes, glottis opens and breathing continues)

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14
Q

Explain reflex arc of swallowing
Controlled variable:
Stimulus:
Sensor:
Input:
Controlled center:
Output:
Effectors:
Response:
Negative feedback:

A

Controlled variable: open and clear back of mouth
Stimulus: food touching palate
Sensor: mechanoreceptor
Input: afferent neuron
Controlled center: medulla
Output: somatic motor neuron
Effectors: skeletal muscle
Response: contract,elevate soft palate; larynx closes and epiglottis moves down; opening of UES (relaxation)
Negative feedback: moves bolus to clear back of mouth

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15
Q

What occurs in the esophageal phase

A

food moves down esophogus by peristalsis

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16
Q

As food moves into the stomach, the LES…

A

relaxes and opens allowing food to enter into stomach

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17
Q

If food gets stuck what occurs?

A

Short reflexes will continue peristalsis

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18
Q

Distinguish between the walls of the esophagus and those represented by small intestine

A

GI tract has smooth muscle
Upper 3rd of esophogus has skeletal muscle
Lower 2/3rds of esophogus has smooth muscle

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19
Q

Stretch of smooth muscle responds by contraction in ENS

A

myogenic reflex

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20
Q

Explain what happens at the cellular level with stretching of smooth muscle

A

stretch activates mechanically gated channels, allowing calcium to enter the cell

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21
Q

Higher calcium concentration where?

A

Outside the cell

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22
Q

Explain what happens at the subcellular level with stretching of smooth muscle

A
  1. calcium in cell binds to calmodulin forming the ca-calmodulin complex
  2. Ca-calmodulin complex activates MLCK
  3. Active MLCK binds to and phosphorylates myosin
  4. Myosin binds to actin, initiating contraction
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23
Q

If MLCK is elevated what occurs:

If you inhibit phosphorylation of myosin:

A

more likely to be contracted

Predict it will lead to muscle relaxation

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24
Q

Explain the reflex arc in esophogus that responds to stretch
Controlled variable:
Stimulus:
Sensor:
Input:
Controlled center:
Output:
Effectors:
Response:
Negative feedback:

A

Controlled variable: Muscle length
Stimulus: Stretch
Sensor: Mechanoreceptor (sensitive to stretch)
Input: Sensory neuron
Controlled center: ENS (interneuron)
Output:Myenteric plexus (innervate smooth muscle)
Effectors: Smooth muscle (contracts in response to ENS input)
Response: Contraction
Negative feedback: Moves bolus and restores muscle length

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25
Q

Describe how the closing of the LES is aided by positive pressure abdominal pressure

A

LES located outside thoracic cavity because it experiences normal atm pressure which helps keep the LES closed, forming a barrier between acid and esophogus

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26
Q

What is Gatroesophogeal reflux disease (GERD)? Who is at risk?

A

High pressure in stomach
At risk: Obsese people, pregnant women, anyone who has overeaten

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27
Q

What is the role of longitudinal muscle? Circular? in the muscularis externia

A

Long= propels food in one direction
Circular= wraps around the intestine and closes off the lumen in contraction

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28
Q

What occurs in the mucosa?

A

90% absorption

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29
Q

What innervates the GI tract?

A

Submucosa

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30
Q

Role of the submucosa

A

Enzyme secretion of glands, filled with BV and glands

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31
Q

The inner most layer, facing the inside of the stomach

A

Gastric mucosa

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32
Q

The gastric mucosa is able to secrete…? What does it contain

A

Mucus and bicarb; G cells, delta cells, and parietal cells

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33
Q

Characteristics of mucus secretion

A

80% carb chains, alkaline, high in bicarb

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34
Q

Only substance secreted by the stomach that’s essential to life

A

Intrinsic factor

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35
Q

Large glycoprotein that complexes with vitamin B12

A

Intrinsic factor

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36
Q

When is vitamin B12 absorbed?

A

When complexed with intrinsic factor (in intenstine)

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37
Q

Explain how acidic environment helps with iron absorption?

A

Iron absorbed as ferrous iron (Fe2+); acidic environment helps prepare the iron absorption in intestine

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38
Q

People taking anti-acids or a proton pump inhibitor can suffer from…

A
  1. Iron mal-absorption (If ferrous iron is oxidized)
  2. Bacterial infections (less acidic enviornment to kill bacteria)
  3. Decreased activation of pepsinogen and protein digestion (pepsin cannot be formed)
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39
Q

Function of mucus

A

lubricates food, protects against acidic stomach

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40
Q

Play a critical role in maintaining mucosal integrity, HCO3- secretion, and mucus production

A

Prostagladins

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41
Q

What is the effect of drugs that inhibit prostaglandins?

A

Drugs: NSAIDS, ibuprofen; ulcers

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42
Q

Intrinsic factor secreted from partietal cells stimulated by…

A

ACh, gastrin, and histamine with vitamin b12 to permit absorption

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43
Q

Explain the long reflex (extrinsic)

A

Chemo/Mechanoreceptor–> sensory neuron–> medulla–> vagus nerve–>smooth muscle cell/gland–> muscle contraction or secretion

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44
Q

What is typically secreted for the long reflex mechanism of acid secretion

A

Acetylcholine release from submucosal plexus and PSNS that binds parietal cell

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45
Q

What is typically secreted for the Short reflex mechanism of acid secretion

A

Acetylcholine release from submucosal plexus and PSNS that binds parietal cell

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46
Q

Explain the short reflex (intrinsic)

A

Chemo/Mechanoreceptor–> sensory neuron–>interneuron–> myenteric/submucosal plexus (ENS)–>smooth muscle cell/gland–> muscle contraction or secretion

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47
Q

What is typically secreted for the paracrine mechanism of acid secretion

A

histamine is released from H cells that bind receptors present in neighboring parietal cells

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48
Q

What is typically secreted for the endocrine mechanism of acid secretion

A

G cells in mucosa secrete gastrin into blood that binds to receptors on the parietal cell and histamine cell (allowing for histamine release)

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49
Q

One cell releases a hormone that affects a neighboring cell (close target), acts on a nearby cell that expresses the hormone’s receptor

A

Paracrine

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50
Q

Hormone released into the blood and effects cells expressing the hormone’s receptor (too far for diffusion)

A

Endocrine

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51
Q

Outputs for Long and short reflex

A

Long- parasym NS
Short- ENS

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52
Q

what is the mechanism for acid secretion in the lumen of stomach

A
  1. Co2 from blood is converted into H+ and HCO3- (by CA)
  2. H+ is pumped against its gradient by proton pump into the lumen of stomach
  3. HCO3- moves into the blood through Cl- exchanger, making blood that moves through stomach more basic (alkaline tide)
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53
Q

What is the proton pump

A

Moves H out and K in through primary transport

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54
Q

Lowering the hydrogen ion concentration results in…

A

CO2 diffusion into the cell

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55
Q

What is the inhibitor of acid secretion and explain how it inhibits?

A

Somatostatin released by delta cells if high H+ in lumen; acts directly on pariteal cell

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56
Q

If someone is over-produicing gastrin what can you expect to happen?

A

increased HCl levels and increased histamine release

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57
Q

An inactive enzyme synthesized and stored intracellularly. Give an example.

A

Zymogen, pepsinogen

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58
Q

Zymogen is released by __ and to be activated….

A

chief cells, requires acid presence

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59
Q

Explain pepsin’s activation, regulation, and function.

A

Activation= pepsinogen activated by HCl in stomach lumen (HCl cleaves pepsinogen into pepsin)
Regulation= by acid secretion in stomach lumen
Function= enzyme responsible for cleaving proteins and peptides in stomach, responsible for 20% protein digestion

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60
Q

Describe how the gastric muscularis promotes mechanical breakup of chyme through peristalsis

A

3 muscle layers: oblique, circular, and longitidudinal
Peristalsis allows mixing and moving of chyme (1 way movement)

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61
Q

Explain the Basal electrical rhythm (BER)

A

Pacemaker cells in stomach generate a spontaneous, rhythmic depolarization—resulting in contraction of the long. muscle

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62
Q

Describe the intrinsic BER

A

Myogenic and submucosal plexus, short reflexes

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63
Q

Describe the extrinsic stimulators of motility in the stomach. Shift? What’s released?

A
  1. Parasym. NS= increased activation shifts the resting MP toward threshold (increases # of AP)
  2. Sym NS= increased activation shifts the resting MP away from threshold (decreasing # of AP)

Parasym NS releases ACH on pacemaker cells
Sym NS releases norepi (inhibitory) on pacemaker cells

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64
Q

Describe the interaction of excitatory and inhibitory stimuli in regulation of gastric emptying

A

Increased PSNS would increase gastric emptying, decreased PSNS would decrease emptying

Increased sym output would lead to less/decreased gastric emptying

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65
Q

When food enters the stomach, what happens to the pH?

When there’s gastric emptying, what happens to the pH?

A

increases, excitatory

decreases, inhibits acid

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66
Q

The myenteric plexus receives its messages from the

A

vagus nerve

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67
Q

Produces peristaltic waves

A

submucosa plexus

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68
Q

Describe the effects of sympathetic and parasympathetic stimulation on the intrinsic activity of the gut….

A

Sympathetic= release NE on smooth muscle and pacemaker cells, inhibits digestive activity (decrease AP)
Parasympathetic= release ACh on smooth muscle and pacemaker cells, stimulates digestive activity (Increase AP)

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69
Q

Biggest contributor to parasympathetics stimulation of GI tract/gut is….

A

Vagus nerve

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70
Q

The ENS serves as the control center for…

A

local short reflexes

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71
Q

The ENS respond to what kind of input from the SNS and PSNS

A

Extrinsic

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72
Q

Stretching activates sensory neurons that increase motility through the…

A

activation of the ENS (stretch increases Ca2+ permeability)

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73
Q

What are the effects of stretch on the smooth muscle GI tissue (from lab)

A

opens the mechanically gated Ca2+ channels, causing Ca2+ to flow into the cell allowing for contraction

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74
Q

What are the effects of Ach on the smooth muscle GI tissue (from lab)

A

As Ach binds to the receptor, it will increase the rate of pacemaker firing and calcium into the cell—increasing contraction/strength of contraction

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75
Q

What are the effects of atropine on the smooth muscle GI tissue (from lab)

A

blocks Ach from binding to and activating the GPCR, relaxing the smooth muscle (no contraction)

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76
Q

What are the effects of epi/norepi on the smooth muscle GI tissue (from lab)

A

As epi binds to the receptor, it inhibits Ca2+ release from the SR and decreases the rate of pacemaker firing–leading to muscle relaxation

Epi/norepi hyper-polarizes the membrane

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77
Q

What are the effects of elevated extracellular K+ on the smooth muscle GI tissue (from lab)

A

cell depolarizes to threshold which promotes pacemaker cells to generate AP’s quicker and increases intracellular Ca2+—-muscle contraction

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78
Q

If you elevate the extracellular K+ on the smooth muscle GI tissue, what happens to the gradient

A

increases the gradient (Increase ECF K+ depolarizes the cell by preventing K+ from exiting)

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79
Q

What are the effects of BaCl–K+ inhibitor on the smooth muscle GI tissue (from lab)

A

BaCl causes our muscles to produce less/weaker contractions because re-polarization inhibits pacemaker cells from reaching threshold as often (intracellular Ca2+ decreases)

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80
Q

Describe the contraction in the intestine (peristaltic waves)

A

A slow wave must reach threshold
1. The depolarization from the AP spreads through the
intestine (gap junctions) depolarizing smooth muscle
cells.
2. Depolarization is sensed by voltage gated Ca2+
channels causing them to open.
3. Ca2+ enters the smooth muscle cells and initiates
muscle contraction.

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81
Q

Distension of the stomach ___ force of contractions and rate of emptying

A

increases

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82
Q

Presence of fat, acid, and amino acids in the intestine ___ gastric motility

A

inhibits

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83
Q

Waves of contraction become stronger as it moves towards the __. What occurs here? What else is affected?

A

antrum; most of mixing, pyloric sphincter starts relaxing (and open)

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84
Q

Somatostatin inhibits acid secretion and ____
Somatostatin is released in response to what?

A

release of CCK and secretin from enteroendocrine cell

Increased H levels, CCK, and secretin

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85
Q

Effects of secretin, CCK, and enteroendocrine cells on gastric emptying/motility

A

inhibit gastric emptying/motility

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86
Q

Force and duration of muscle contractions are directly related to…

A

frequency of AP’s

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87
Q

As a peristaltic wave moves toward the antrum, what happens to the pyloric sphincter?

A

Opens and then shuts allowing small amount of chyme to be released from stomach into SI

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88
Q

Where are precursor cells located

A

Crypts of L

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89
Q

Replace the dying epithelium by dividing and pushing cells upward to repolarize the villi tip from hypoxic environment

A

Precursor cells

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90
Q

90% of villi cells are

A

absorptive cells

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91
Q

Abundant in the first part of the intestine when we have a high level of acid coming from chyme in the stomach

A

Goblet cells

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92
Q

Entereoendocrine cells are located

A

villi

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93
Q

Describe the countercurrrent mechanism of villi

A

Tip of the villi becomes hypoxic because the oxygen is high as it enters the villi, diffuses down gradient into the venous blood (arterial and venous blood mixed) :cells then die

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94
Q

Highest turnover rate of cells is in the

A

SI

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95
Q

Relationship between precursor cells and chemotherapy/radiation

A

Chemo targets= fast dividing cells such as precursor cells

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96
Q

Role of circular folds in the SI

A

maximize absorption by increasing SA and increase surface diffusion

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97
Q

Why is it important to neutralize chyme

A

Enzyme function
Mucosal protection
Micelle formation

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98
Q

Secretin is released by ___ in response to ___

A

enteroendocrine cells, increased H+

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99
Q

Explain the mechanism of secretin acting on the pancreas and SI

A
  1. As CO2 diffuses into a ductal cell in pancreas, HCO3 and H+ is formed by CA
  2. HCO3- is pumped down gradient though HCO3/Cl- exchanger (secondary transport) into lumen of SI from pancreas
  3. HCO3- helps neutralize gastric acid
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100
Q

Secretin goes to the __, activates ___ to release ___ from _____ to _____

A

pancreas, ductal cells, bicarb, pancreatic duct to SI

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101
Q

Secretin in the blood has what effect on gastric motility

CCK in the blood has what effect on gastric motility

Gastrin has what effect on gastric motility

A

Inhibits

Inhibits

Stimulates

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102
Q

If enteroendocrine cells cannot secrete secretin (if there’s a mutation for example) what effect does this have?

A

no bicarb production and cannot neutralize pH in intestine

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103
Q

If there’s a plug in the pancreatic duct or an obstruction in duct, what effect does this have?

A

Bicarb cannot move into the SI (low pH in SI) but secretin is still being secreted

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104
Q

Hormone released from mucosal cells in response to fasting

A

Motilin

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105
Q

Motilin stimulates the Migrating Motor Complex that….

A

increases intestinal peristalsis (long peristalic wave from stomach to LI)

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106
Q

CCK is released from ____ when in the presence of ___

A

enteroendocrine cells; fats, peptides, and carbs

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107
Q

Signals the release of digestive enzymes from the pancreas and bile from liver into SI

A

CCK

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108
Q

Describe CCK secretion

A
  1. When an increase in lipase, CCK secreted from enteroendocrine cells into the blood
  2. From the blood CCK….
    - Targets pancreas to release digestive enzymes to digest lipids that go to the lumen of SI
    - Targets gall bladder to secrete bile to emulsify fat in prep for absorption
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109
Q

What cell releases digestive enzymes and zymogens in the pancreas

A

Acinar cells

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110
Q

Breaks up fat allowing digestive enzymes to digest and breakup fats and amino acids

A

Bile

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111
Q

Potent stimulator for acid secretion

A

Gastrin

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112
Q

Gastrin is secreted from the ___

A

Antrum by G cells

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113
Q

How does gastrin work to stimulate gastric motility

A

Gastrin binds to receptors on the parietal cells (for acid release) and histamine cells

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114
Q

What controls the movement of peristalsis and segmentation

A

ENS: Intrinsic

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115
Q

Serve as a control for short reflexes

A

Interneurons in the ENS

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116
Q

Stretch activates mechanoreceptors on sensory nerves that ____ motility by activating the ____

A

increase, myenteric plexus

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117
Q

Acid in the SI activates ___ on the sensory nerves that increase ____ by activating the ___

A

chemoreceptors, bicarb secretion, submucosal plexus

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118
Q

What controls the forward movement and mechanical breakup of the chyme

A

Long reflex (ANS)

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119
Q

Explain how the ANS/neural (long reflex) effects gastric motility (digestive activity)

A

Parasym (vagus) NS= cholinergic fibers (Ach) stimulates digestive activity
Sympathetic= NE inhibits digestive activity

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120
Q

Pancreas has an exocrine function because

A

it releases secretin and CCK into pancreatic DUCT

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121
Q

Describe protein digestion

A
  1. Digestive enzymes from acinar cells enter into the small intestine (as zymogens) from pancreatic duct
  2. Trypsinogen is activated by brush border enzymes on microvilli (convert into trypsin)
  3. Trypsin activates other inactive enzymes to break down proteins
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122
Q

Protein is broken down into…

A

Smaller peptides then single AA

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123
Q

Describe carbohydrate digestion

A

Glucose polymers to disaccharides to monosaccharides (broken down by amylase)

Digestive enzymes breakdown glucose

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124
Q

Describe fat digestion…

A

Large lipid globules + bile salts= small lipid globules

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125
Q

Don’t break bonds but separating larger lipids into smaller lipids

A

Emulsification, bile salts

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126
Q

Describe the process of fat absorption

A
  1. Bile salts from liver coat fat droplets (emulsification)
  2. Lipases from pancreas break down fat into monoglycerides and fatty acids
  3. Monoglycerides and fatty acids enter cells of SI by diffusion
  4. Absorbed fats combine with cholesterol and proteins in the cell to form chylomicrons (lipid droplet)
  5. Chylomicrons are removed by the lymphatic system by exocytosis into the vena cava
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127
Q

What effects do the parasympathetic and sympathetics have on the pancreas

A

Parasympathetic= enhances rate of secretion of alkaline juices (bicarbonate) and digestive enzymes
Sympathetic= inhibits rate of secretion of alkaline juices (bicarbonate) and digestive enzymes

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128
Q

Identify the 3 main vessels that move blood and bile within the liver:
What do they carry?
Direction of flow?

A
  1. Hepatic artery= arrives rich oxygenated blood, toward the central vein
  2. Hepatic portal vein= nutrients, toward the central vein
  3. Bile duct= bile from hepatocytes, away from central vein
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129
Q

Why do the hepatic portal vein and hepatic artery have in common?

A

Same direction of flow, oxygen and nutrients sent to every hepatocytes before dumped into central vein (mixed)

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130
Q

Describe carb absorption

A

Sodium moves down gradient into cell and glucose moves up gradient into the cell by sodium glucose transporter (2°)

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131
Q

Carbohydrate absorption prevents…

A

Glucose from leaving in feces

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132
Q

What are the ways protein can be absorbed (most to least common)

A
  1. Amino acids enter the cell by 2° transport by Na+ down gradient (uses energy from Na/K ATPase) & AA in cell enter blood by facilitated diffusion
  2. Di and tri-peptides co transport with H+ into the cell
  3. Peptides carried across cell by transcytosis
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133
Q

Is Na+ high or low in the interstitial fluid

A

High

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134
Q

What enhances and inhibits the rate of secretion of alkaline juices (bicarbonate) and digestive enzymes from the pancreas

A

Ach parasympathetics=enhance
NE sympathetics= inhibits

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135
Q

Describe the properties of a hormone

A

Potent in small concentrations, regulate biological functions, work thru certain receptors, work with other hormones to elicit a cellular response

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136
Q

Chemical substance secreted by a group of cells into bodily fluids that has a physiological effect on other cells that express the hormones receptors

A

Hormone

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137
Q

Steroid hormone derivative

A

Cholesterol

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138
Q

What hormone can diffuse through the membrane vs. cannot, dissolves in plasma

A

Diffuse through= steroid (non-polar, lipid soluble)
Dissolves in plasma, no carrier= protein

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139
Q

In steroid hormones…
Chemistry:
Half life:
Transportation:
Receptor location:
Mechanism of action:

A

Chemistry: slow acting but long lasting
Half life: longer (longer to degrade)
Transportation: protein carrier in the blood
Receptor location: Intracellular receptor (in cell)
Mechanism of action: initiates cellular transcription

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140
Q

How is the steroid hormone slow acting but long lasting

A

Slow acting: activate transcription and protein synthesis
Long lasting: protein carriers shield the steroid hormone from degradation

141
Q

Most common protein carrier

A

Albumin

142
Q

Steps for the mechanism of action for steroid hormones

A
  1. Lipid soluble hormone diffuses through plasma membrane
  2. Hormone finds receptor in cell and binds to it
  3. Hormone finds a specific DNA region
  4. Produce mRNA —transcription of gene for effector protein
  5. mRNA read by ribosome
  6. Synthesis of effector protein—causes cellular response
143
Q

Example of steroid hormones

A

Sex hormones

144
Q

In body builders, testosterone is taken exogenously, which results in ___ formation because ___. As a result, they take a ___

A

Estrogen, balance

Often take an aromatase inhibitor

145
Q

In protein hormones…
Chemistry:
Half life:
Transportation:
Receptor location:
Mechanism of action:

A

Chemistry: fast acting but short lasting
Half life: short (not shielded in blood)
Transportation: dissolved in the blood
Receptor location: plasma membrane receptor
Mechanism of action: binds plasma membrane receptors to second messenger system

146
Q

How are protein hormones fast acting but short lasting?

A

Fast acting= amplification
Short acting= freely degraded, not shielded like steroid hormones

147
Q

Mechanism of action in protein hormone?

A
  1. Protein hormone binds to receptor in plasma membrane
  2. Binding activates a protein kinase
  3. Protein kinase phosphorylates effector protein
  4. Activates a cellular response
148
Q

In what hormone is there no new protein synthesis occurring

A

Protein

149
Q

Why can a small amount of protein hormone have s large cellular effects

A

Amplification

150
Q

Activation at each step activates a larger and larger number of proteins in…

A

Amplification of 2nd messenger systems

151
Q

Ability of a target cell to respond to a hormone

A

Sensitivity

152
Q

What’s a reflection of the number of receptors

more__ = more receptors

A

Sensitivity, sensitive

153
Q

Decrease in number of receptors

Increase in number of receptors

A

Down regulation, up regulation

154
Q

What happens to receptor expression and sensitivity in down regulation vs. up regulation

A

Decreases vs increases

155
Q

Chronic stress__ regulates GH receptor

Exercise __ regulates insulin receptor number on muscle cells

A

Down
Up

156
Q

Hormone A has a small response but exposure of hormone A to this type of hormone results in a greater response

A

Permissive effect

157
Q

Epinephrine weakly stimulates lipolysis but in the presence of T3 and T4 it strongly stimulates lipolysis (increase sensitivity)

A

Permissive hormone effect

158
Q

Hormone A and B have a small effect on their own but when released together their effects are greater than the sum of the individual hormones

A

Synergistic hormone effects

159
Q

Glucagon and epinephrine work to increase blood glucose levels on their own, but together blood glucose rises even further then the sum of the 2 individual effects

A

Synergistic

160
Q

The binding of receptors to second messenger systems amplify the response of a signal in what type of hormone effect

A

Synergistic

161
Q

One hormone opposes the actions of another hormone

A

Antagonistic

162
Q

Insulin and glucagon have opposing results; insulin decreases glucose levels but glucagon increases glucose levels

A

Antagonistic hormone effect

163
Q

Once an endocrine cell secretes a hormone into a fluid (like the blood) the hormone then…
1.
2.

A
  1. Travels until it reaches a capillary bed where it diffuses out into the extracellular space (interstitial fluid)
  2. Hormone binds to cells w its receptor and activates response
164
Q

Explain carbohydrate metabolism function of the liver

A

Helps store excess glucose as glycogen and helps replenish plasma when glucose levels low

165
Q

Explain conjugation of toxic substances in the liver

A

Increases the hydrophilicity of a substance (more contained and less toxic)

166
Q

Where are conjugated substances of the liver released?

A

Released into blood/ cleared or secreted by kidneys (smaller particles) OR released with bile and cleared by intestine (large molecules)

167
Q

How can the gallbladder get stimulated or inhibited?

A

Stimulated= CCK (parasympathetics) act directly on smooth muscle of gall bladder
Sympathetic inhibit smooth muscle contraction

168
Q

Why is emulsifying fats by bile important?

A

Increases SA for digestive enzymes to degrade lipids

169
Q

Bile salts remain in the small intensive until….

A

Absorbed by the ileum

170
Q

How are bile salts recycled?

A

Reabsorbed bile salts return back to gallbladder and wait to be secreted; small amount lost in feces

171
Q

If bile salts/acids aren’t returned to the liver, what will the response be?

A

Liver increases bile production

172
Q

Contractions of the haustra in the small intestine help….

A

Squeeze out water from feces

173
Q

Function of mass movements of LI

A

Peristaltic contractions help propel feces forward

174
Q

Internal anal sphincter:

Type of muscle?
Function?

A

Involuntary/smooth
When feces touches this it relaxes

175
Q

External anal sphincter:
Type of muscle?
Function?

A

Voluntary/ skeletal

Have control over when we “hold it”

176
Q

What reflex plays a larger role in inhibiting defecation

A

Long reflex

177
Q

Explain the defecation reflex for long reflex

A

Stretch

Mechanoreceptor

Sensory nerve

Integrating center: sacral spinal nerve

Efferent nerve: parasympathetic activation

Increased peristaltic waves in colon and rectum

Relaxations of sphincters=defecation

178
Q

Explain the short reflex defecation reflex

A

Stretch

Mechanoreceptor

Sensory nerve

Integrating center: interneuron

Efferent nerve: myenteric plexus

Increased peristaltic waves in colon and rectum

Relaxations of sphincters=defecation

179
Q

stimulating
hormones that target other glands
resulting in the release of a second
hormone (peripheral hormone)

A

Tropic hormones

180
Q

Tropic hormones activated the release of what tier of hormones

A

3 for cellular response

181
Q

move through the blood until they reach their target organ in the body

A

Peripheral hormones

182
Q

A hormone that is secreted from the
pituitary that does not elicit the
secretion of a new hormone is a…

A

Direct hormone

183
Q

A patient has a tumor in the anterior pituitary that causes hyper release of stimulating hormones.

In regards to the cortisol pathway, which hormones would you expect to be elevated? What would be low?

A

ACTH and cortisol are elevated and CRH is low

184
Q

A person with Graves disease produces proteins called antibodies that mimic the actions of TSH (The body thinks the antibodies are TSH).
If you were to take a blood sample from this patient, describe the levels of TRH, TSH and T3 and T4 that you would expect to see.

A

TRH and TSH are decreasing
T3 and T4= increasing

185
Q

Explain the 3 tiers of the anterior pituitary

A

Tier 1= releasing hormones from hypothalamus
Tier 2= delivery of hypothalamus hormones and release of AP hormones (stimulating hormones)
Tier 3= delivery of AP hormones to target organs (peripheral hormones)

186
Q

What is an extension of the hypothalamus and how

A

Posterior pituitary: neurosecretory cell bodies originate in the hypothalamus and axons extend into PP

187
Q

What hormones do neurosecretory cells produce

A

Oxytocin and ADH

188
Q

Doesn’t have specialized cells that secrete hormones

A

Posterior pituitary

189
Q

Doesn’t synthesize hormones, hormones come from cells in hypothalamus

A

Posterior pituitary

190
Q

Contains a set of hormone, special secreting cells that are sensitive to hormones secreted from hypothalamus

A

Anterior pituitary

191
Q

Hormones secretes by the hypothalamus will activate a subset of cells in the ___ that respond by secreting a 2nd hormone into the blood

A

Anterior pituitary

192
Q

The neurons in the hypothalamus are connected to the anterior pituitary by

A

Portal system

193
Q

Functions of growth hormone?

A
  1. Metabolic switch (direct)= occurs during short periods of fasting to maintain blood sugar (body switches from using glucose for energy to using fatty acids)
  2. Promote growth (tropic)= GH activates the release of insulin such as (IGF-1)
194
Q

Promotes the growth and development of bones, neurons, and other tissues

A

IGF-1

195
Q

Effect of cartilage cells with IGF

A

Cartilage cells increase with IGF

196
Q

What happens to the cartilaginous epiphyseal plate before puberty

A

when stimulated by IGF —> causes you to grow

197
Q

What happens to the growth plate after puberty

A

Seals and calcifies (adult height)

198
Q

What is growth hormones role after puberty

A

Maintains bone

199
Q

Excessive bone growth=
Excessive growth causes bone thickening and soft tissue overgrowth=

A

Gigantism
Acromegaly

200
Q

Increasing the peripheral hormones has what effect on releasing and stimulating hormones

A

Inhibits them (tier 3 inhibits tier 1 and 2)

201
Q

Increasing the stimulating hormones has what effect on the releasing hormone

A

Inhibits (tier 2 inhibits 1)

202
Q

Inhibiting the release of releasing and stimulating hormone allows for…

A

Regulation of the amount of peripheral hormone

203
Q

Stimulates gluconeogenesis, raise BP, anti-inflammatory

A

Cortisol

204
Q

What’s the stimulus for cortisol release

A

Stress (low blood sugar, trauma, cytokines)

205
Q

Describe the cycle of cortisol release and negative feedback

A

Stress—> CRH released through the hypothalamic portal system —> ACTH released in bloodstream —> cortisol released from the adrenal gland

Increases in cortisol inhibits the release of CRH and ACTH

206
Q

Regulates BMR, enhance actions of epi, regulate development of nervous tissue and growth

A

Thyroid (T3 and T4)

207
Q

Stimulus of thyroid (T3 and T4)

A

Low blood levels of T3 and T4

208
Q

Describe the cycle of thyroid (T3 and T4) release and negative feedback

A

Low levels in blood —> TRH released through the hypothalamic portal system -> TSH released in bloodstream —> release of T3 and T4

Increasing T3 and T4 inhibit the release of TRH and TSH

209
Q

Stimulus of growth hormone release

A

Hypoglycemia, low fatty acids in blood, and deep sleep

210
Q

Describe the cycle of growth hormone release and negative feedback

A

Stimulus—> GHRH released through the hypothalamic portal system —> GH released —> release of IGF 1 (tropic) and direct effects on metabolism

Increasing GH and IGF-1 inhibits the release of GHRH and GH

211
Q

Protein digestion first occurs in the stomach before the small intestine by…

A

Pepsin, from pepsinogen and acidic environment

212
Q

Absorption of water relies on the absorption of

A

Sodium

213
Q

If sodium moves into the cell, then the water concentration on the outside of the cell ___

A

Increases

214
Q

Increased testosterone in the plasma would feedback negatively to the hypothalamus __________ GnRH.

A

Inhibiting

215
Q

Decreased GnRH leads to a decrease in

A

FSH and LH

216
Q

Is homeostasis a steady state or equilibrium

A

Steady state

217
Q

Dynamic process that uses the systems of the body to maintain a constant internal environment

A

Homeostasis

218
Q

What fluid is regulated by homeostasis

A

Interstitial fluid

219
Q

Interstitial fluid is directly related to

A

Plasma, if plasma o2 drops then interstitial o2 drops

220
Q

What is not considered a part of the internal environment

A

Intracellular fluid

221
Q

Semen composed of

A

Sperm cells and seminal plasma

222
Q

Most semen comes from

A

Accessory organs

223
Q

Support and protect the developing sperm

A

Sertoli cells

224
Q

Describe the sperm anatomy

A

Head = acrosome, helps egg and sperm fuse in fertilization (contains enzymes)
Midpiefe= mitochondria to provide atp for tail
Tail= allow movement in ejaculation

225
Q

Describe meiosis in males and females in reproductive system

A

Parent cell germ cell
1. Diploid (23 and 23)
2. Crossing over occurs: 46 and 46
3. Divides into 2 cells (each with two 23 - cells are genetically different from parent)
4. Those cells divide into 4 cells, haploid that are unique

In females: 1 parent cell= 1 egg cell (oocyte) and 3 polar bodies

226
Q

Describe mitosis in reproduction

A

Parent cell is somatic cell
1. Begins with a diploid cell
2. Dna replication, cell contains 2 sets of 46
3. Splits into two cells each with two sets of 23 (genetically identical)

227
Q

Explain the process of gametogenesis/spermatogenesis

The the phase of spermiogenesis

A

Spermatids are formed and differentiation of spermatids to sperm cells

228
Q

Explain the process of gametogenesis/spermatogenesis

The the phase of spermiation

A

Sperm released from serotoli cells and enter seminiferous tubules

229
Q

Explain the process of gametogenesis/spermatogenesis

The phases in order

A

Spermatocytogenesis
Spermiogenesis
Spermiation

230
Q

Explain the process of gametogenesis/spermatogenesis

The the phase of spermatocytogenesis

A
  1. Spermatogonium undergoes Mitosis which produces and replenishes stem cells
  2. Meiosis 1: produces two secondary spermatids (haploid)
  3. Meiosis 2: produces 4 haploid spermatids
231
Q

Produce testosterone

A

Leydig cells

232
Q

Increase transport of cholesterol into these cells, increase transcription of enzyme involved in testosterone production

A

Leydig cells

233
Q

Leydig cells are stimulated by

A

LH

234
Q

Testosterone from the leydig cells diffuse over to…

A

Sertoli cells (and blood) and stimulate spermatogenesis

235
Q

FSH stimulates the production of substances that promote the development of sperm in what cell

A

Sertoli cell

236
Q

What produces ABP and inhibin

A

Sertoli cells

237
Q

Function of ABP

A

Binds diffusing testosterone to keep levels high in Sertoli cells enhancing spermatogenesis

238
Q

When sperm production levels are high enough, the Sertoli cell produces

A

Inhibin

239
Q

What cell expresses inhibin produced?

What produces inhibin?

A

FSH producing cells
Sertoli cells

240
Q

Inhibin inhibits what

A

FSH and LH release in AP

241
Q

Feedback regulation or hypothalamus and AP (regulation of LH and fsh)

A

Testosterone

242
Q

Describe the relationship of testosterone during pre-puberty

A

Very sensitive to testosterone and little testosterone can turn off hormones in hypothalamus and AP, hypothalamus has an increased number of testosterone receptors

243
Q

Describe the relationship of testosterone during puberty

A

Brain becomes less sensitive to testosterone, results in increased hormone and ABP production

244
Q

What two things do you need to produce and/or restore sperm production if decreased

A

FSH and testosterone

245
Q

Describe the pathway of testosterone release

A

Low testosterone levels (stimulus)—> GnRH released from hypothalamus through portal system —> LH and FSH released from AP into bloodstream

246
Q

Pathway of FSH in males

A

Stimulates ABP and inhibin production—> spermatogenesis

247
Q

Describe the pathway of LH in males

A

LH stimulates Leydig cells —> testosterone produced —> diffuses into Sertoli cell

248
Q

Negative feedback of testosterone release and inhibin: increase in inhibin…

Increases in testosterone…

A

Increases in inhibin, inhibits the release of FSH and LH (TIER 2)

Increases in testosterone inhibits GnRH and LH and FSH (tier 2 and 1)

249
Q

Used by sperm to make Atp

A

Citric acid

250
Q

Clots semen after ejaculation

A

Clotting enzymes

251
Q

What in the seminal secretions is protective from the acidic environment

A

Bicarbonate and clotting enzymes

252
Q

Break down clots in seminal secretions once acidic environment is neutralized

A

Proteolytic enzymes

253
Q

Antibiotic in seminal secretions

A

Seminal plasmin

254
Q

Development of male or female internal and external genitalia

A

Phenotypic sex

255
Q

Do the genotypic and phenotypic sex match always?

A

Don’t always match if XY male doesn’t have SRY gene

256
Q

SRY gene
Located where:

A

Y chromosome

257
Q

Stimulates neutral gonadal tissue differentiation into testes (testes formation)

A

SRY gene

258
Q

The lack of the SRY gene results in

A

Female genitalia

259
Q

Two functions of the ovaries

A

Produce eggs and secrete sex hormones

260
Q

Follicles contain a __ and once it’s matured it is a __

A

Oocyte, ovum

261
Q

In oogenesis, for every 1 oogonium there’s..

A

1 ovum (gamete) formed

262
Q

What happens in meiosis 1 of oogenesis

A

Produces a primary oocyte from oogonium

263
Q

What happens in meiosis 2 in oogenesis

A

Secondary oocyte and 1st polar body is produced, ovulation of secondary oocyte, after fertilization meiosis 2 resumes and oocyte turns into ovum and 2nd polar body

264
Q

What joins together in ferlization?

A

Secondary oocyte and sperm cell

265
Q

Explain the pathways for female sex hormones and estrogen release (LH and FSH pathway)

A

GnRH released from hypothalamus —> LH and FSH released into blood

LH in blood —> stimulates theca cells to produce androgens —> androgens diffuse into granulosa cells —> converted to estrogen

FSH in blood —> stimulate estrogen production —> when estrogen levels rise, granulosa cells secrete inhibin

266
Q

Explain the negative and positive feedback of female sex hormones…

Increases in inhibin….
Mid levels of estrogen…

A

Increases in inhibin, inhibits FSH and LH (tier 2)

Mid levels of estrogen inhibits GnRH, FSH, and LH release

Positive feedback: estrogen continues to be produced and granulosa cells continue to divide until LH spike (ovulation)

267
Q

Works as a transcription factor what 2 female hormones?

A

Estrogen and progesterone

268
Q

Endometrial proliferation, granulosa cell expansion (division) increases this hormone…

A

Estrogen

269
Q

Prepares the uterine tract for pregnancy, growth and differentiation of endometrium (becomes thicker and turns into a gland during implantation)

A

Progesterone

270
Q

Suppresses myometrium contractile activity (keeps smooth muscle quiet until labor)

A

Progesterone

271
Q

Inhibits milk production, from the placenta

A

Progesterone

272
Q

When FSH levels are too high, what is released

A

Inhibin

273
Q

Explain why perimenopausal women have anovulatory periods

A

Harder to ovulate because no period, LH spike; GnRH, LH, and FSH increase and estrogen decreased

274
Q

Explain why a young girl may have a period without ovulation?

A

Estrogen levels may increase and proliferation of the uterus may occur but not enough to activate LH spike, differentiation of uterus

275
Q

In a period, over time, follicles will die and estrogen will decrease resulting in…

A

Shedding of endometrium

276
Q

Explain how oral contraceptives inhibit ovulation?

A

Taking exogenous estrogen and progesterone inhibits GnRH, LH, FSH and turns off granulosa and theca cells —> no estrogen or LH spike

277
Q

When you take oral contraceptives, what happens to endogenous estrogen and proliferation or endometrium

A

Decreases

278
Q

The sugar birth control pills represent….

A

Corpus albicans (what’s shed in period)

279
Q

What happens during menopause

A

Ovaries run out of follicles, estrogen decreased and GnRH, LH, and FSH increased

280
Q

Relationship of estrogen and sensitivity in pre- puberty and during puberty…

A

Pre= hypothalamus super sensitive to estrogen
During= brain less sensitive, less receptors (increased GnRH, LH, FSH, estrogen, androgens, and inhibin)

281
Q

If pregnancy occurs, what happens to the corpus luteum?

A

Will stay alive and continue to produce hormones until the placenta can take over

282
Q

If corpus luteum dies during pregnancy what happens….

A

No glycogen produced, lining can’t thicken for egg (miscarriage)

283
Q

If pregnancy doesn’t occur what happens to the corpus luteum?

A

It does and forms corpus albicans, doesn’t produce hormones and endometrium sheds (menstruation)

284
Q

Order of cycle in female

A

Follicular phase, contains proliferation phase

Ovulation

Luteal phase, contains secretory phase of egg implants

Menstruation if not pregnant

285
Q

What happens during the proliferation phase in female

A

Uterine lining thickens, From menstruation shedding lining (result of high estrogen)

286
Q

Describe the follicular phase if there are low levels of estrogen

A
  1. Releases GnRH from hypothalamus
  2. LH and FSH released from AP (targets ovaries)
  3. LH goes to Theca cells to stimulate androgen production
  4. FSH accumulates in antrum/follicle and stimulates estrogen production in granulosa cells
  5. Granulosa cells take up androgens and make estrogen
  6. Estrogen expands granulosa population (which thickens lining) and they keep dividing in ovary until high enough estrogen levels
  7. Estrogen from follicle stimulates endometrial growth and proliferation
287
Q

Has cholesterol backbone, aromatase modifying

A

Androgen

288
Q

The dominant follicle will accumulate the most… and is the most sensitive

A

FSH

289
Q

When there are midrange levels of estrogen, what occurs

A

Inhibits GnRH, LH, FSH
Estrogen produced until ovulation

290
Q

When there are high levels of estrogen, what occurs

A

Activates the release of GnRH because LH spike

291
Q

Result of LH spike that releases the egg, marks the end of follicular phase and star of luteal phase

A

Ovulation

292
Q

How does ovulation occur?

A
  1. High levels of estrogen from granulosa cells stimulates GnRH release
  2. Increased GnRH results in a surge of mainly LH from AP
  3. Increase LH from high estrogen=LH spike which released the egg
293
Q

What determines when ovulation occurs and how?

A

Follicle; once it makes enough estrogen

294
Q

What happens at the secretory phase in females

A

Glycogen is produced, GnRH, LH, FSH inhibited; promotes differentiation of lining converting it into a gland

295
Q

Progesterone inhibits what tiers and why?

A

1 and 2, you don’t want those hormones being released and want to see if egg gets fertilized

296
Q

Explain the steps in the luteal phase

A
  1. Ruptured follicle turns into corpus luteum
  2. CL secretes high levels of progesterone and some estrogen
  3. Progesterone promotes differentiation of lining and turns it into a gland for egg
  4. Estrogen helps with growth and maintenance of endometrium
297
Q

Primary hormone producing structure in luteal phase

A

Corpus luteum

298
Q

The corpus luteum consists of

A

Granulosa cells

299
Q

More receptors for __ = most responsive follicles

A

LH and FSH

300
Q

Describe what happens when egg is fertilized by sperm?

A
  1. Sperm binds to ZP3 receptor on egg’s surface
    2.Triggers the acrosomal reaction and release of enzymes onto egg’s surface
  2. Acrosomal rxn dissolves a hole in the zona pellucida allowing the sperm entrance into egg
301
Q

fusion of sperm to egg activates pathways that block

A

polyspermy

302
Q

How is polyspermy prevented?

A

Immediately after egg is fertilized, it initiates cortical rxn

303
Q

Explain the cortical reaction, what two things occur to prevent polyspermy?

A
  1. Deactivation of all remaining ZP3 receptors (prevents other sperm from binding egg)
  2. Depolarization of oocyte: hardens zona pellucida
304
Q

Describe dizygotic twins and monozygotic twins

A

Dizygotic- 2 eggs, 2 sperm (fraternal)
Mono- 1 egg, 1 sperm (identical twins)

305
Q

Describe the embryonic development of forming a blastocyst

A
  1. Zygote divides by mitosis
  2. Development of many cell types start by day 5 to form blastocyst
    - Trophoblast and inner cell mass
306
Q

Forms the placenta, forms outside shell of blastocyst

A

trophoblast

307
Q

Located inside blastocyst, will become the embryo

A

inner cell mass

308
Q

Embryo burrow deep into uterine wall

A

implantation

309
Q

Inner cell mass aligns with the wall of uterus and releases enzymes to attach to wall in what

A

implantation

310
Q

The endometrium is rich in ___ due to what hormone

A

glycogen and blood vessels, progesterone

311
Q

The blastocyst secretes __ in what phase

A

HCG, implantation

312
Q

IN the implantation phase, the release of ___ breaks down the uterine wall to gain access to the blood source

A

proteolytic enzymes

313
Q

What phase do cells in blastocyst become specialized, 3 layer differentiate

A

Gastrulation

314
Q

Becomes the lining of GI in fetus=
Becomes skin and nervous tissue=
BEcomes muscle, bonds, and connective tissue

A

endoderm
Ectoderm
Mesoderm

315
Q

Where does gas and nutrient exchange occur in mother and fetus

A

chroionic villi and mother blood supply

316
Q

What is released from mom to fetus and how:

What is released from fetus to mom and how:

A

Mom to fetus: by veins, O2, nutrients, hormones, antibodies, and drugs
Fetus to mom: by arteries, CO2, metabolic waste, hormones

317
Q

Females who are pregnant do not get periods because

A

high progesterone, inhibits menses

318
Q

Produced by placenta

A

Estrogen and progesterone

319
Q

How does progesterone keep myometrium quiescent (non-contractile)

A
  1. Increased K+ channel expression (easier for K+ to leave, hyper-polarizes membrane)
  2. Suppresses gap junctions between smooth muscles
320
Q

Progesterone inhibits what

A

Gnrh, FSH, LH, and prolactin

321
Q

Main hormone producer in pregnancy

A

placenta

322
Q

Estrogen increases what receptor during pregnancy

A

oxytocin

323
Q

How does HCG communicate with the CL to increase production of estrogen and progesterone

A

bind LH receptor

324
Q

Known as the pregnancy hormone, increases in first trimester until placenta takes over

A

HCG

325
Q

HCG signals from __ to ___

A

embryo, CL

326
Q

Stages of labor

A

Stage 1: dilation of cervix (to 10cm)
Stage 2: expulsion of baby
Stage 3: placental delivery

327
Q

What helps to soften cervix in first stage of labor

A

prostaglandins

328
Q

What increases in the second stage of labor? When does this stage end?

A

Increased oxytocin release stimulates strong uterine contractions, ends when baby is born

329
Q

What occurs to prevent hemorrhage in placental delivery

A

Blood vessel constriction and nursing baby

330
Q

Positive feedback regulation of labor:
Controlled variable:
Stimulus:
Sensor:
Input:
Controlled center:
Output:
Effectors:
Response:
positive feedback:

A

Controlled variable: muscle length of cervix
Stimulus: Stretch
Sensor: Mechanoreceptor
Input: sensory neuron
Controlled center: hypothalamus (PP)
Output: oxytocin release
Effectors: uterus
Response:smooth muscle contraction
Positive feedback: more stretch of cervix

331
Q

What ends positive feedback loop in labor

A

delievery of baby

332
Q

Describe milk letdown
Stimulus:
Receptor:
Input:
Controlled center:
Output:
Effectors:
Response:

Positive or negative feedback

A

Stimulus: nursing at breast
Receptor: mechano
Input: sensory nerve
Controlled center: hypo (PP)
Output: oxytocin release from PP
Effectors: myoepithelial cells on mammary glands
Response: contraction and milk ejection

Positive

333
Q

In pregnant females the ability to increase…. goes away. The reflex target is mainly on the ___ rather than the ___

A

TPR; heart, blood vessels

334
Q

Explain the baroreceptor reflex arcs of an decrease BP as stimulus
Controlled variable:
Receptors:
Input:
Control center:
Output:
Effectors:
Response:

A

Controlled variable: BP
Receptors: baroreceptors
Input: stretch less, decreases AP rate
Control center: medulla
Output: Increased symp and decreased parasym stimulation
Effectors: heart- increase heart rate and contractility
Response: increase BP

335
Q

Explain the baroreceptor reflex arcs of an increase BP as stimulus
Controlled variable:
Receptors:
Input:
Control center:
Output:
Effectors:
Response:

A

Controlled variable: BP
Receptors: baroreceptors
Input: stretch more, increases rate of AP
Control center: medulla
Output: decreased symp and increased parasympathetic stimulation
Effectors: decrease heart rate/contractility and vasodilation/decreased TPR
Response: decreased bp

336
Q

Stroke volume depends on

A

contractility

337
Q

A drop in TPR (low BP) will activate baroreceptor reflex arc–whats the correct input and response

A

Input: less stretch, less AP firing, increase SNA
Response: increase contractility and heart rate

338
Q

passing of solutes from the blood into nephron in glomerulus

A

filtration

339
Q

If freely filtered, not secreted and not absorbed, clearance ______ GFR

If reabsorbed: clearance ___ GFR

If secreted: clearance ___ GFR

A

equals

less than Gfr

greater than gfr

340
Q

what happens to the capillary pressure and GFR when the afferent arteriole dilates

A

both increase; increase in hydrostatic pressure= increase GFR, decrease in hydrostatic pressure= decrease GFR

341
Q

If clearance increases, and something is not reabsorbed or secreted: what happens to GFR

A

increases as well

342
Q

How would you expect drug dosage to change during pregnancy (Ex. lithium)

A

Clearance of drugs are higher during pregnancy (increased dosage)

343
Q

Why is it important to increase blood volume during pregnancy?

Increases blood volume, also increases what during pregnancy?

A

To meet increased demand for nutrients, oxygen, and waste removal due to growing baby

HR, CO, and contractility

344
Q

What organ in females also produces renin during pregnancy

A

Ovaries

345
Q

Increase in renin release results in increased Na and H2o reabsorption (increases blood volume): How?

A

Angiotensin II increases aldosterone production: insertion of new Na channels and Na/K ATPases, increases Na reabsorption

Also increases ADH production (from posterior pituitary): insertion of aquaporin channels, increases H2o reabsorption

346
Q

Highest Na+ concentration and highest H2o water concentration

A

lumen of distal nephron

347
Q

Lowest Na+ concentration and lowest H2o water concentration

A

cytoplasm of cell

348
Q

As Na+ leaves the lumen of the collecting duct, what happens to H2O Concentration

A

increases in the lumen

Human Physiology (14 decks)

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