CV and Endocrine Review

Name 3 formed elements found in whole blood. (Use scientific terms.)

1. 1% white blood cells (leukocytes)

2. platelets (thrombocytes)

3. 44% red blood cells (erythrocytes)

Which formed element is used to determine a hematocrit?

The % of red blood cells.

Name 3 ways in which the structure of red blood cells illustrates their function in the body.

1. Biconcave shape (like an inner-tube) allows for greater surface area.

2. Round sides make for efficient flow through blood vessels.

3. Erythrocytes have no nucleus & few organelles so they don’t use up the oxygen while transporting it.

Why can’t oxygen travel through the blood on its own?

Oxygen is nonpolar, so it is not soluble in blood.

How many oxygen molecules can one hemoglobin protein carry?

one hemoglobin can hold 4 oxygen molecules.

In the center of each heme group can be found an atom of which element?

an Iron atom

What is the function of the cells known as leukocytes? (General description)

Leukocytes= White blood cells

Function: to protect the body from foreign cells or substances

Name 4 ways erythrocytes differ from leukocytes.

Erythrocytes differ from leukocytes by: 

1. Outnumber leukocytes 1,000 to 1

2. Mature cells do not contain nuclei

3. Live only 100-120 days

4. Confined to the bloodstream

Name 2 differences between granulocytes and agranulocytes.

1. Granulocytes have lobed-shaped nuclei and contain visible granules

2. Agranulocytes have spherical or kidney-shaped nuclei and no visible granules

Blood cells are formed by what process? Where does this occur?

Hematopoiesis = the process of blood cell formation. Occurs in the red bone marrow of adults

Which blood type is known as the universal donor?  Which is the universal recipient?

Universal donor: Type O

Universal recipient: Type AB

Which 2 heart chambers contain deoxygenated blood? Which 2 heart chambers contain oxygenated blood?

Right atrium and right ventricle contain deoxygenated blood. Left atrium and left ventricle contain oxygenated blood. 

Briefly explain the 3 steps of hemostasis

1. When thyroxine levels get too high, the hypothalamus is triggered to stop the impulse

2. Hypothalamus secretes hormones into the pituitary

3. Thyroid secretes thyroxine into blood, increasing metabolism

Name the three layers of the pericardium and give their functions.

Fibrous, serous,  and visceral pericardium. 

Fibrous pericardium: provides protection and anchors the heart in place

Serous pericardium (made of parietal & visceral): provides lubricating fluid

Name the three layers of heart tissue.

Epicardium, myocardium, endocardium

What are the 2 cardiovascular circuits and where do they deliver blood?

1. Pulmonary circuit: carries blood from the heart to the lungs

2. Systemic circuit: carries blood from the heart to the body tissue and back

Describe the path of an impulse leaving the SA node.

SA node →cardiac pacemaker →AV node→AV bundle and the bundle branches→purkinje fibers

What are the two major portions of the cardiac cycle?

systole and diastole

What is the formula for calculating cardiac output?

Cardiac output = heart rate x stroke volume

Describe 2 differences between veins and arteries.

Arteries: Thick walls, especially in tunica media layer and receive blood from heart under high pressure

Veins: Thin walls and receive blood from tissues under low pressure

Arteries and veins have 3 tissue layers.  Name them starting with the outermost layer.

Tunica externa (tunica adventitia): fibrous connective tissue to support & protect

Tunica media: thicker layer of muscle

Tunica intima: slippery, thin layer

Contrast 2 ways in which the nervous and endocrine systems control the body.

The nervous system can respond quickly to stimuli, through the use of action potentials and neurotransmitters. Responses to nervous system stimulation are typically quick but short lived. The endocrine system responds to stimulation by secreting hormones into the circulatory system that travel to the target tissue.

How do hormones affect the right cells and not others?

Target cells have receptors for specific hormones. If the hormones contact cells without these target cells, they will have no effect.

Contrast the way lipid-soluble hormones & water-soluble hormones cause cellular changes.

Lipid soluble hormones can pass directly through the target cell membrane forming a  hormone- receptor complex. Water soluble hormones are amino acid-based molecules that are not able to pass through the membrane. They bind to receptors on the outside of the target cell, which activate a 2nd messenger to mediate the response to the target cell.

What are the 3 ways a gland can be stimulated to release hormones?

Hormonal stimuli, humoral stimuli, and neural stimuli

Which gland is known as the “master gland”? Why does it have this name?

The pituitary gland because it controls many other glands in the body.

Name 4 hormones secreted by the anterior pituitary and give their functions.

1. Thyroid-stimulating hormone (TSH): Causes thyroid to produce thyroxine

2. Adrenocorticotropic hormone (ACTH): Stimulates adrenal glands

3. Growth Hormone (GH): Stimulates growth in bones and muscles

4. Melanocyte stimulating hormone (MSH): Stimulates melanocytes to produce melanin

Name 2 hormones secreted by the posterior pituitary and their functions.

1. Antidiuretic hormone: Increases water retention in kidneys, decreasing urine production

2. Oxytocin (OT): Stimulates contraction of uterus during childbirth and promotes release of breast milk

What portion of the brain controls the pituitary through neural and hormonal stimulation?

The hypothalamus

What is the major secretion of the pineal gland and what is its function?

The main secretion of the pineal gland is melatonin, which regulates sleep and wake cycles.

Name 2 hormones secreted by the thyroid and list their functions.

1. Calcitonin: Reduces the calcium levels in the blood

2. Thyroid Hormones: Regulate metabolism and body heat production, controls cellular oxygen usage, and maintains blood pressure

What hormone is secreted by the parathyroid?  What is its function?

Produces parathyroid hormone, which has the opposite function from calcitonin. Parathyroid hormone brings calcium out of the bones and into the bloodstream for use by cells.

Contrast the exocrine and endocrine portions of the pancreas.

Exocrine: uses ducts

Endocrine: uses ductless glands and the endocrine part of the pancreas is made of groups of cells called the islets of Langerhans that look like tiny islands.

Explain how the two hormones of the pancreas regulate blood glucose levels.

Beta cells → Insulin → Lower blood glucose levels

Alpha cells → Glucagon → Raise blood glucose levels

Although the thymus gland is considered part of the endocrine system, its functions relate more to what system?

immune system

Name 3 hormones produced by the male and female gonads

Estrogen, Progesterone (female) and Testosterone (male)

What are the 2 types of feedback loops?  Give an example of each within the body.

1. Positive: amplifies change/process

2. Negative: maintain stability (homeostasis)

What 2 situations may result from an improperly functioning endocrine gland? (Hint: Both situations start with the letter “h”.)

1. Hyposecretion: not enough hormone is released

2. Hypersecretion: too much hormone is released