A&P Lab 12 - Class 11: The Circulatory System I

What makes up blood?

Cells and cell fragments, ground substance (plasma), and dissolved protein fibers (appear as fibrin strands during clot formation)

What is blood a transport medium for?

* Oxygen
* Carbon dioxide
* Nutrients
* Hormones
* Wastes

How does circulating blood help maintain homeostasis?

* Regulates pH
* Adjusts body temperature
* Maintains osmotic pressure of cells

What are the two components of blood?

* Formed elements (cells and cell fragments)
* Plasma

How much blood is there in in an adult male body vs. an adult female body?

* Male: 5-6L
* Female: 4-5L

What is the approximate ratio of red blood cells to white blood cells?

Around 700:1

Describe red blood cells

* Non-nucleated.
* Bi-concave discs.
* Contain oxygen carrying pigment (hemoglobin).

What are the two major groups of leukocytes?

* Granulocytes (have a large number of cytoplasmic granules).
* Agranulocytes (have no apparent cytoplasmic granules).

Types of granulocytes

* Neutrophils
* Eosinophils
* Basophils

Neutrophils

* Forms 60% - 70% of the leukocyte population.
* Phagocytic.
* Function in the destruction of pathogenic micro-organisms and other foreign matter.
* Easily identified by nucleus which is normally segmented into three lobes.

Wright’s stain

Stain most commonly used to examine blood cells.

Contains:

* Eosin: Acid dye
* Methylene blue: basic dye

Eosinophils

* Forms 2%-4% of the leukocyte population.
* Play a role in the control of local responses associated with allergic reactions.
* Important in the defense against multicellular parasites.
* Two characteristics help identify this:
* Reddish-orange globular granules in the cytoplasm.
* Nucleus is usually segmented into two lobes.

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Basophils

* Forms 0.5%-1% of the leukocyte population.
* May be involved in allergic reactions, releasing heparin and histamine to enhance the inflammatory response.
* Has an S-shaped nucleus.

Lymphocytes

* Most numerous of the agranular leucocytes.
* Forms 20%-25% of the leukocyte population.
* Produce antibodies and other agents involved in the immune process.

Monocytes

* Largest of the white blood cells.
* Forms 3%-8% of the leukocyte population.
* Their large size is their best identifying characteristic.
* Highly phagocytic.
* Nucleus can be round, kidney-shaped, or other shapes.
* Large amount of cytoplasm present.

Platelets

* Disc-shaped.
* Contain many granules, but no nucleus.
* Help stop blood loss from damaged vessels by forming a platelet plug.
* Helps promote blood clotting.

Purpose of a differential white blood cell count

Determine the percentage of each of the five types of leukocytes in a sample of blood.

Leukemia

Refers to a group of cancerous conditions characterized by an uncontrollable proliferation of leukocytes.

What can a high neutrophil percentage signify?

* Bacterial infection
* Poisons

What can a low neutrophil percentage signify?

A toxic reaction to certain drugs

What can a high eosinophil percentage signify?

* Allergy
* Parasitic infection

Give some examples of things that can cause high lymphocyte count

* Infectious mononucleosis
* Measles
* Mumps
* Tuberculosis

Give some examples of things that can cause high monocyte count

* Tuberculosis
* Protozoan disease
* Hodgkin’s disease
* Infectious mononucleosis

Hematocrit

Value: About 45%.

Percentage of total blood volume occupied by RBCs.

How is hematocrit determined?

(Volume of blood that’s only occupied by RBC).

By centrifuging a sample of heparinized blood (heparin prevents the clotting of blood).

Normal value of hematocrit in males vs. females

Males: 40-54%

Females: 38-46%

What does an abnormally red blood cell count usually signify?

Anemia

What are some causes of anemia?

* Certain deficiencies (ex. iron or B12)
* Increased destruction or malformation of red blood cells (due to severe infection, sickle cell anemia, incorrect transfusion, …)

Which blood evaluations are the most important when it comes to an anemia diagnosis?

Hematocrit and hemoglobin

Polycythemia

Condition characterized by an above normal amount of red blood cells.

Hematocymeter

A visual method of usage for counting red blood cells

In which cases might white blood cell count be below normal values?

* Measles
* Infectious hepatitis
* Cirrhosis of the liver
* If receiving radiation or antibiotic therapy

What’s the healthy white blood cell count in a healthy individual?

Ranges between 5,000 - 10,000

Leukocytosis

White cell count over over 10,000

Leukopenia

White cell count significantly less than 5,000

What is the oxygen and carbon carrying cell?

Red blood cell (erythrocyte)

Which cell helps form a clot to stop bleeding?

Platelet

What is another name for white blood cell?

Leukocyte

Polycythemia vera

Abnormal increase in red blood cells

Which blood cell comprises 20-25% of all white blood cells?

Neutrophils

Which cell has a horseshoe-shaped nucleus, and the cytoplasm has no granules?

Monocyte

What is the least numerous leukocyte?

Basophil

Anemia

A deficiency in the number of RBCs, or decreased content of hemoglobin in the blood

A cell involved in response to parasitic worms and allergies

Basophils

Blood test that measures the percentage of total blood volume made up of RBCs

Hematocrit

Value: Red blood cell count for an adult female of 3million cells/mm^3

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a) Normal or abnormal?

b) Cause?

a) Abnormal

b) Anemia/low iron levels

Value: A differential white blood cell count indicating an eosinophil value of 10%

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a) Normal or abnormal?

b) Cause?

a) Abnormal

b) Allergy/fungal infection

Value: A differential white blood cell count indicating a monocyte value of 12%

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a) Normal or abnormal?

b) Cause?

a) Abnormal

b) Infectious disease (ex. mononucleosis)

Value: An adult male hemoglobin concentration of 10g/100mL

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a) Normal or abnormal?

b) Cause?

a) Abnormal

b) Anemia, vitamin deficiency

Value: White blood cell count for an adult of 3800cells/mm^3

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a) Normal or abnormal?

b) Cause?

a) Normal

The only blood available for a transfusion is B+. Indicate if the following blood types are compatible for transfusion of B+ blood:

a) Patient B-

b) Patient O+

c) Patient AB+

d) Patient A+

a) No. This patient has Rh antibodies.

b) No. O types can only receive other O types (with respect to Rh presence).

c) Yes. B antigen and Rh factor is already present (there are no contrasting antibodies).

d) No. A antigen has B antibody present.

Movement of veins and arteries (away/towards heart?)

Veins: Toward.

Arteries: Away.

Where does exchange of materials between the circulatory system and the tissues occur?

Through capillaries (thin-walled)

Why do arteries have thick walls?

They must withstand the pressure of heart beats

Why do veins have valves?

Valves prevent backflow of blood when they’re returning towards the heart.

Explain the following of an artery:

a) Tunica interna (intima)

b) Tunica media

c) Tunica externa (adventitia)

a) Innermost layer. Composed of a single layer of endothelial cells. Some larger arteries also have an internal elastic membrane (elastica interna).

b) Tunica media: The middle layer, consisting mainly of smooth muscle and elastic fibers (run in a circular direction around the lumen).

c) Outer layer, composed of fibrous connective tissue and fat cells. In some larger arteries, the tunica media and tunica externa are separated by an elastic membrane (elastica externa).

Explain the following of a vein:

a) Tunica interna

b) Tunica media

c) Tunica externa

a) Consists of a layer of endothelial cells. No elastic interna.

b) Composed mainly of circular smooth muscle cells.

c) Composed of loose fibrous connective tissues with fat cells.

Elastica interna

Extra layer of internal elastic membrane of larger arteries

Upper two chambers of the heart

Atria

Lower two chambers of the heart

Ventricles

Why do the atria have thinner walls?

They receive blood which is returning to the heart from the veins.

Why are there coronary blood vessels on the heart?

The heart does not use the blood which pumps through it, so it requires its own circulation

Right and left coronary arteries arise from the:

Base of the aorta

Where do coronary veins drain blood from?

Where do they they return the blood to?

Capillaries.

Coronary sinus (large vein that opens into the right atrium).

The wall of the right ventricle is thinner than the left. Why is this?

The wall of the right (pulmonary) ventricle is thinner than the left (systemic) due to the distance needed to pump

a) What is the pulmonary trunk?

b) Where does it originate?

c) What is it the start of?

a) A large artery.

b) The right of the heart.

c) The pulmonary circuit of blood flow.

Does the pulmonary trunk carry oxygenated or deoxygenated blood?

Deoxygenated

Role of the aorta

(Artery) carries oxygenated blood from the left ventricle into the systemic circulation.

The human heart has three major branches off the aorta.

Name them.

* Brachiocephalic artery
* Left common carotid artery
* Left subclavian artery

Superior vena cava

Large vein which delivers venous blood collected from the head, neck, and arm regions to the right atrium.

Inferior vena cava

Large vein which delivers venous blood collected from the lower body regions to the right atrium.

Pulmonary veins

These are visible on the dorsal surface of the heart.

They carry oxygenated blood from the lungs to the left atrium of the heart.

Purpose of heart valves

To promote unidirectional flow of blood within the heart

What is the opening and closing of heart valves a response to?

Pressure differences

The valve at the base of the aorta is called the:

Aortic semilunar valve.

The valve which separates the right atrium and the right ventricle is called the:

Right atrioventricular (tricuspid) valve

How are cusps (of heart valves) anchored to the heart?

Papillary muscles, through fibrous cords called chordae tendineae

Valve separating the left atrium and left ventricle:

Left atrioventricular (bicuspid) valve.

How does the right atrium receive blood from the systemic circulation?

Through the superior vena cava and inferior vena cava, and the coronary sinus.

a) The superior vena cava carries blood collected from the:

b) The inferior vena cava carries blood collected from the:

a) Head, neck, and arms.

b) Inferior regions of the body.

Where does the coronary return blood from?

The myocardium

Where in the heart does venous blood pass from/into?

What is the pathway after this?

From the right atrium into the right ventricle.

It is then pumped to the lungs by the way of the pulmonary trunk.

What are the two smaller arteries that the pulmonary trunk splits into?

Left and right pulmonary arteries (which continue to the lungs).

Trace the pathway of blood as it flows through the heart.

* Starting with deoxygenated blood in the inferior/superior vena cava.
* Ending with the aortic arch.

Deoxygenated blood inferior/superior vena cava → right atrium → tricuspid valve → right ventricle → pulmonary S.L. valve → pulmonary trunk → right and left pulmonary arteries → lungs → right and left pulmonary veins → left atrium → bicuspid valve → left ventricle → aortic S.L. valve → ascending aorta → aortic arch

Major circulatory pathways of the body:

* Pulmonary circulation
* Systemic circulation

Brachiocephalic artery

Branches to form the right common carotid artery and the right subclavian artery.

Where do right and left subclavian arteries supply blood to?

Arms, shoulders, chest, and back.

Axillary artery

When the subclavian artery runs laterally to reach the underarm region.

Brachial artery

When the subclavian artery continues as the axillary artery once it reaches the underarm, and carries down into the arm.

What do the right and left common carotid arteries each divide into?

* Internal carotid artery
* External carotid artery

(Just posterior of the larynx)

What do internal carotid arteries supply blood to?

Most of the structures of the head and neck.

What is the continuation of the aortic arch called?

The descending aorta.

When does the descending aorta become the thoracic aorta, and the abdominal aorta?

Thoracic aorta: Once passed through the thoracic cavity.

Abdominal aorta: After passing through the diaphragm.

Which arteries supply blood to the intercostal muscles?

Intercostal arteries (branching from the thoracic aorta).

What is the first major branch from the abdominal aorta?

Celiac artery

Three important branches of the celiac artery

* Common hepatic artery
* Left gastric artery
* Splenic artery

Where does the common hepatic artery supply blood to?

Liver, gallbladder, stomach, pancreas, duodenum.

Where does the left gastric artery supply blood to?

Stomach and inferior portion of the esophagus

Where does the splenic artery supply blood to?

Spleen, stomach, and pancreas.

a) Where is the superior mesenteric artery found?

b) What does it supply blood to?

a) A short distance posterior/distal to the celiac artery

b) The mesentery, small intestine, pancreas, and part of the large intestine.