Physiology Week 3 Flashcards Preview

MSAP Physiology > Physiology Week 3 > Flashcards

Flashcards in Physiology Week 3 Deck (33):
1

List the 4 Components of Gastric Juice:

1. HCl
2. Pepsinogen
3. Intrinsic Factor
4. Mucous

2

What is the only ESSENTIAL component of gastric juice and why?

Intrinsic Factor: Necessary for absorption of Vitamin B12 in the Ileum

3

4 Types of cells in Oxyntic glands and their secretions:

1. Surface Epithelium: Alkaline, visible mucous
2. Mucous Neck Cell: Clear Mucous
3. Parietal (Oxyntic) Cell: HCl and Intrinsic Factor
4. Chief (Peptic) Cell: Pepsinogen

4

Achlorhydria:

Decreased Parietal (Oxyntic) Cell mass and low HCl secretion due to lack of Intrinsic Factor, ultimately resulting in Pernicious Anemia.

5

Describe G-Cell secretion:

G-Cells secrete Gastrin into the CIRCULATION, not into the ducts of the pyloric glands, and it travels to act on Parietal Cells to release HCl and Intrinsic Factor.

6

Where in the stomach are each of the types of glands/cells located?

1. Gastric (Oxyntic) Glands: BODY of stomach
-Parietal (oxyntic) Cells: HCl and Intrinsic Factor
-Chief (peptic) Cells: Pepsinogen
2. Pyloric Glands: ANTRUM of stomach
-G-Cells: Gastrin into CIRC.
-Mucous Neck Cells: Mucous, HCO3-, Pepsinogen

7

What are the 3 main functions of HCl in the stomach?

1. Activate Pepsinogen
2. Create optimal environment for Pepsin
3. Kill Bacteria

8

The process of HCl secretion gives an overall net secretion of ______ across the _____ membrane, and an overall net absorption of ______ across the ______ membrane.

1. Secrete HCl --> Luminal Membrane
2. Absorb HCO3 --> Basolateral Membrane

9

Describe the function of Omeprazole:

To treat GERD, this drug inhibits the H+-K+-ATPase at the luminal membrane of parietal cells to prevent HCl formation in the stomach.

10

What cells release Histamine and how does it elicit its effect?

1. ECL cells adjacent to Parietal cells in stomach body.
2. Hist binds H-2 receptor which uses a G-alpha-S subunit to increase cAMP and ultimately activate the
H+-K+-ATPase to release H+.

11

How is the activity of ACh different in the stomach from that of Histamine?

ACh from the Vagus Nerve binds an M-3 receptor on parietal cells and activates a G-alpha-Q subunit to increase IP3 and ultimately activate the
H+-K+-ATPase to release H+.

12

How is the activity of Gastrin different in the stomach from that of Histamine?

Gastrin from the G-Cells binds a CCK-B receptor on parietal cells and activates a G-alpha-Q subunit to increase IP3 and ultimately activate the
H+-K+-ATPase to release H+.

13

Explain the function of the 3 blockers of HCl formation/secretion in the stomach:

1. Atropine = M-3 Antagonist
2. Tagamet/Zantac = H-2 Antagonist
3. Omeprazole = H+-K+-ATPase Pump Inhibitor

14

Cephalic Phase ACh secretion:
1. Stimuli: ____
2. Both Mechanisms: ______

1. Smelling, chewing, tasting, etc.
2. Direct: (Vagus) ACh --> M-3 receptor
Indirect: (Vagus) GRP --> G-Cell --> Gastrin

15

Main Difference between Myocardial and SA Node Action Potentials:

SA Node Action Potentials have NO resting membrane potential, they are dynamically changing.

16

How is the frequency of SA action potentials (and therefore HR) increased?

By increasing the rate of depolarization via the Funny Sodium Channels to reach threshold faster.

17

Between which two conducting structures of the heart does the "inter-nodal" delay occur?

The AV Node and Bundle of His

18

Explain Ca2+ induced-Ca2+ release:

Membrane depolarization in cardiomyocytes triggers the opening of voltage-gated L-type Ca2+ channels. That influx of Ca2+ triggers the opening of Ryanodine Receptors in the cell which release stored Ca2+ into the cytosol to allow contraction.

19

What are the two mechanisms of removing intracellular Ca2+ to stop cardiomyocyte contraction?

1. Ca2+-ATPase: Pumps Ca2+ back into storage.
2. Na+/Ca2+-Exchanger: Pumps Ca2+ out of the cell.

20

What receptor do Epi/NE bind in cardiomyocytes?

B-1 Receptors

21

How is Mean Arterial Pressure calculated?

MAP = Diastolic + 1/3 Pulse Pressure

22

Where are Baroreceptors found in the body?

On Arteries that supply the Brain and the Heart:
-Brain: At Carotid Sinus
-Heart: At Aortic Arch

23

Equation for BP:

BP = SV x TPR

24

Equation for CO:

CO = HR x SV

25

What is the flow sensor of the kidney? How does it measure flow?

1. The Juxtaglomerular Apparatus
2. Detecting the amount of salts passing through the glomerulus.

26

Describe the 5 Functions of Angiotensin 2:

1. Activates Thirst Center --> Inc. AVP secretion
2. Inc. Vasoconstriction --> Inc. TPR --> Inc. BP
3. Dec. GFR --> Dec. Urine Output
4. Inc. Reabs. of filtrate at Nephron
5. Inc. Aldosterone prod. at Adrenal glands

27

Function of Renin:

Converts Angiotensinogen --> Angiotensin 1

28

Function of ACE (in lungs):

Converts Angiotensin 1 --> Angiotensin 2

29

The R.A.A.S. activity is a graded response that can be altered by ________.

The Sympathetic Nervous System output in response to baroreceptor stretch at the nephron.

30

Stenosis:

Narrowing of a heart valve causes turbulence to the blood flow.

31

Equation for Ejection Fraction:

SV/EDV

32

The ______ is also known as the Total ventricular Volume.

EDV

33

Equation for Flow:

Q = k(P1-P2)
OR
Q = (P1-P2) / R
OR
CO = MAP/TPR