Question

1. Describe structural difference of the two main types of hormones, their mechanisms of action on target cells and the three types of stimuli regulating their secretion.

2. Describe how red blood cells are produced and based on their structure, how they transport gases in the blood.

3. Describe in detail the four regulating mechanisms of stroke volume and how it influences cardiac output.

I was looking for help in these three questions for my anatomy and physiology class. Thanks!

Answer 1

1) There two main types of harmones based on their structural. Composition

I) peptide harmones: These are made up of proteins

II) Steroid harmones: These are made up of lipids

Mechanism of action:

Peptide harmones are Lipid insoluble. They binds to the receptors present on the surface of the target cell and send signal to nucleus via second messengers.

Steroid harmones are Lipid soluble. They can easily pass through the cell membrane. Hence their receptors are present directly in cytoplasm or in nucleus where they bind and produces their action.

Three types of stimuli causing secretion of harmones are

I) humoral: control of Harmone release in response to changes in extracellular fluids.

II) harmonal :release of harmones in response to other harmone

III) Neural : release in response to stimulus from neurons

2) Red cells are produced from the bone marrow cells. These are produced in response to oxygen carrying capacity of the blood under the the control of negative feedback. When hypoxia occurs, it is sensed by kidney cells which release Erythropoietin which acts on the bone marrow to form and release red blood cells.

Within the red blood cells are present Hemoglobin which is a iron containing protein molecule. This molecule has the capacity to bind with four molecules of Oxygen through iron. With the help of that, they transport gases in the blood.

3) mechanism of regulation of stroke volume

I) Preload

-increased preload increases the stroke volume by increasing the venous return and end diastolic volume

II) Contractility

It decreases the end systolic volume and their by increases the stroke volume

III) After load

- it increases the end systolic volume and thereby decreases the stroke volume

VI) heart rate

-increased heart rate decreases the stroke volume.

Cardiac output is directly proportional to Stoke volume. Increase stroke volume tends to increase Cardiac Output