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There are three types of muscle tissue: skeletal, cardiac, and smooth. Describe the cellular orientation (for example long or short, branching or not, types of junctions between cells, etc.) and explain why this orientation is dictated by the type of contraction for the organ that contains this type of muscle?

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Reid Wolff
Reid WolffLv2
28 Sep 2019

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Related questions

receptor

Agonist

antagonist

a1

Norephinephrine

Phenylephrine

a2

Phenoxybenzamine

Prazosin

B1

Clonidine

Yohimbine

Norephinephrine

Propranolol

Epinephrine

Metoprolol

Isoproterenol

Dobutamine

B2

Epinephrine

Proranolol

Norepinephrine

Butoxamine

Isoproterenol

Albuterol

Nicotinic

Ach

Curare

Nicotine

Hexamethonium

Muscarinic

Ach

Atropine

Assume all the chemicals in the table are available to you.

You are given a piece of smooth muscle tissue, you stimulate it with Norepinephrine and find the muscle responds with contractions. Your hypothesis is that the muscle contraction is caused by the activation of α1 adrenergic receptors. Now you need to design an experiment protocol to test your hypothesis.

Background knowledge: The figure below is an experiment setup, the red tissue in the organ bath is the smooth muscle tissues. In this kind of experiment smooth muscle tissue is minimally stretched vertically by two hooks or clips in the organ bath filled with physiological saline solution (PSS). Agonist is added to the PSS to challenge the muscle tissue, muscle contraction is sensed by a force transducer at the top and force is recorded by a computer. Adding antagonist before adding agonist blocks agonist action. PSS may or may not be changed, it depends on your purposes, e.g. if you want to block a type receptors, then you do not want change PSS after you add antagonist to the PSS. Your correct step is that you add antagonist to PSS, wait some time, and add agonist, you keep both antagonist and agonist in the PSS so that you can judge if the receptor blockage by antagonist abolish the agonist action.

The key to this assignment is that you eliminate possible cross-activities of agonists. Cross-activity means an agonist activate more than one types of receptors, you need block each type of the receptor in order to see what type of the receptor is activate to cause contraction. This muscle tissue can have both α and β receptor types and their subtypes, you need to demonstrate convincingly that you only stimulate α1 receptors.

Write an experimental protocol to demonstrate your work, for each step in the protocol you write the chemical(s) you add, why you add, what result you are expecting to see e.g. contract, relax, no response. If the step is to wash the tissue with fresh PSS, then you do not need to indicate the responses.

Here is an example of the answer.

step

chemical added

response

1.

epinephrine, activate alpha and beta receptors,

blood vessel ring contract slightly.

2.

wash with PSS

3.

alpha receptor antagonist and norepinerphine, block NE activating alpha receptor.

blood vessel ring should not contract.

4.

wash with PSS

5.

…

…

6.

…

…

Discuss your protocol to show the relation between activation of α1 receptors and the vascular smooth muscle contraction.Design the experiemnt and its conclusion/ results.

1) The external layer of the heart wall is the

Multiple Choice

endocardium.

myocardium.

epicardium.

parietal pericardium.

2) Check all that are characteristics of cardiac muscle.

Check All That Apply

Cells are long and cylindrical.

Cells are short and branching.

Cells have multiple nuclei at the periphery of the cell.

Cells have one or two nuclei in the center of the cell.

They are composed of thick and thin filaments.

The functional contractile unit is the sarcomere.

3) Match the chamber of the heart with the structure(s) from which it receives blood.

Coronary sinus

Pulmonary veins

Right atrium

Left atrium

Match each of the options above to the items below.

Right atrium

Right atrium Open choices for matching

Right ventricle

Right ventricle Open choices for matching

Left atrium

Left atrium Open choices for matching

Left ventricle

4) The less extensive distribution of T-tubules contributes to the more delayed onset and prolonged contraction of cardiac muscle tissue compared to skeletal muscle tissue.

True or False

5) The cells of the ___________ act as the heart's pacemaker, which establishes the pace for cardiac activity.

Multiple Choice

atrioventricular (AV) node

sinoatrial (SA) node

atrioventricular (AV) bundle

Purkinje cells

6) Match the cardiac vein with its description.

Travels close to the right marginal artery

In posterior interventricular sulcus

In anterior interventricular sulcus

In the posterior portion of cornary sulcus

Match each of the options above to the items below.

Great cardiac vein

Great cardiac vein Open choices for matching

Middle cardiac vein

Middle cardiac vein Open choices for matching

Small cardiac vein

Small cardiac vein Open choices for matching

Coronary sinus

7) Parasympathetic innervation to the heart comes from the medulla oblongata via the left and right ___________ nerves.

8) Check all that are components of the sympathetic innervation of the heart.

Check All That Apply

Cervical sympathetic ganglionCervical sympathetic ganglion

Spinal cordSpinal cord

Vagus nerve (CN X)Vagus nerve (CN X)

Cardiac nerveCardiac nerve

Sympathetic postganglionic axon

9) Check all that occur during ventricular contraction.

Check All That Apply

The AV valves open to allow blood to enter the ventricles from the atria.The AV valves open to allow blood to enter the ventricles from the atria.

The semilunar valves remain closed to prevent backflow of blood into the ventricles.The semilunar valves remain closed to prevent backflow of blood into the ventricles.

The semilunar valves open to allow blood to flow into the large arteries.The semilunar valves open to allow blood to flow into the large arteries.

The AV valves close to prevent backflow of blood into the atria.

1. Be able to define the following terms: releasing hormone,inhibiting hornone, trooic hormone, nontropic hormones,neurosecretory cells.

2. What are hormones?

3. What are two specific differences between the endocrine andnervous systems?

4. What are the four different types of cell signaling?

5. What are the three types of hormonal control pathways? Givean example of each.

6. What is local regulator?

7. What type of feedback is a common feature of pathways thatcontrol homeostasis?

8. What are the three major classes of molecules that functionas hormones? Which are water-souble and which are lipid-souble?

9. Signaling by a hormone involves three key events. What arethey?

10. What is the correlation between solubility of a hormone andthe location of its receptors?

11. In addition to receptor location, water-soluble andlipid-soluble hormones also exhibit additional differences in theirresponse pathways. What are these differences?

12. What is signal transduction pathway?

13. Why can the same hormone have different effects on differentbody tissues?

14. Liver cells and the blood vessels of skeletal muscle cellshave identical surface receptors for epinephrine, yet the responeof these two cells types is dramatically different. Explain howthis is possible.

15. In the "fight or fight response" the release of epinephrinefrom the adrenal medulla cause skeletal muscle blood vessels todilate while simultaneously constricting blood vessels of theintestine. Explain how this is possible.

16. List the three types of local regulators discussed in classand explain their function.


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