Lab 7: (PT. 1 - The Cardiovascular System) The Cardiovascular System II & the Lymphatic System

List 4 major functions of the Cardiovascular System

1. Transportation

   • transports blood to deliver O2, nutrients, hormones, etc. to cells while removing waste products like CO2 & urea

2. Protection

   • defends against infections through WBCs & antibodies; forms clots to prevent blood loss

3. Thermoregulation

   • maintains homeostasis by distinuting heat and adjusting blood flow

4. Circulation

   • ensures continuous movement of blood

   • maintains blood pressure

   • gas exchange w/ capillaries

Which circuit is where oxygen supplies and which is where CO2 is removed?

pulmonary circuit → CO2 eliminated

systemic circuit → O2 supplied to all tissues

Which ventricle has thicker walls? Why does this difference exist?

left ventricle → needs to generate much higher pressure to pump oxygenated blood through the systemic circuit (all over the body)

whereas…

right ventricle → only needs to pump deoxygenated blood to the pulmonary circuit (lungs)

Do arteries or veins carry blood away from the heart?

arteries

Trace the pathway of blood through the systemic circuit

1. Left Ventricle

2. Aorta

3. Arteries

4. Arterioles

5. Capillaries

6. Venules

7. Veins

8. Vena Cavae

9. Right Atrium

thje pressure in the venulas & veins is so low that the blood cannot rise against gravity. In the venous system, blood flows back toawrds the heart w/ the help of 3 mechanisms:

1. Valves

   • folds of inner layer of veins permit only one-way blood flow

2. Skeletal Muscle Pump

   • compression of blood vessels by skeletal muscle contraction

3. Respiratory Pump

   • during inhalation, contraction of the diaphragm compresses the abdominal veins, pushing blood into the decompressed thoracic veins

   • during exhalation, the diaphragm relaxes, & the venous valves prevent backflow of blood

Briefly describe the 3 layers (tunics) of blood vessels

1. Tunica Intima

   • Endothelium; surrounded by basement membrane

2. Tunica Media

   • smooth muscle; allow vasoconstriction

   • thicker in arteries w/ elastic membrane b/c of high pressure

3. Tunia Externa

   • outer layer; contains nerves

Which epithelium lines blood vessels?

simple squamous

describe location of the ascending aorta & the area/organ supplied

location:

• extend upward from aortic valve

• becomes aortic arch

are/organ supplied:

• heart

describe location of the aortic arch & the area/organ supplied

location:

• continuation of the aortic arch

area/organ supplied:

• divides into L/R common carotid artery, & L/R subclavian artery, & brachiocephalic trunk

What is the funcion of the cerebral arterial circle?

cerebral arterial circle → ring-shaped anastomosis of arteries at the base of the brain that ensures constant blood supply to the brain; many alternate routes

Name the blood vessel that passes through the transverse foramina of the cervical verebrae

vertebral artery

The celiac trunk branches into a number of arteries, including the common hepatic & splenic arteries. Name at least 5 structures or organs these blood vessels supply.

1. spleen

2. stomach

3. pancreas

4. duodenum

5. liver

6. gallbladder

What is the function of valves in the peripheral veins? (veins located in the limbs)

ensure one-way blood flow back up to the heart without any pressure by closing valves; combat gravity & backflow

Would you expect valves in veins to be visible in a cross-section slide?

No; they are spaced intermittently along veins & slides are usually cut between valves

Describe the 3 mechanisms that cause venous blood to flow back to the heart.

1. Valves

   • permit only one-way blood flow, prevent backflow

2. Skeletal Muscle Pump

   • compression of blood vessels by skeletal muscles pushes blood upwards

3. Respiratory Pump

   • inhalation → diaphragm contracts and compresses abdominal veins, pushing blood back up to thoracic veins

   • exhalation → diaphragm relaxes & valves close to prevent backflow

What is the source of blood in the hepatic portal system?

deoxygenated (but nutrient rich) blood from the Gastrointestinal (GI) tract, spleen, & pancreas

Why is blood in the hepatic portal vein carried to the liver before it reurns to the systemic veins?

For processing:

• regulates blood glucose

• processes amino acids

• packages lipids

• detoxifies blood

• defends against pathogens before being spread systematically