Human Physiology Exam 2 Part 4

Layers of artery

Endothelium, epithelial tissue, elastic tissue, smooth muscle and fibrous tissue

Layers of arteriole

Endothelium and smooth muscle

Layers of capillary

Endothelium

Layers of venule

Endothelium and fibrous tissue

Layers of veins

Endothelium, epithelial tissue, elastic tissue, smooth muscle and fibrous tissue

Which segment of the vascular system is the pressure reservoir?

Arteries, thicker walls

Which segment of the vascular system volume reservoir?

Veins, valves

What are the factors to facilitate venous return?

venous smooth muscle contraction, the skeletal muscle pump, the respiratory pump and one-way valves in veins

What are varicose veins? Cause and common risk factors?

Bulging veins caused by weak or damaged vein walls and valves. Risk factors include age, gender, family history, sitting or standing for long periods, pregnancy, constipation, a tumor, or overweight and obesity

What factors affect fluid resistance through a tube (Poiseuille’s equation)?

Resistance = 8 Lη / πr^4, where L - length of the tube, r – radius of the tube η - viscosity of the medium π - constant

What is the most effective factor to change resistance?

radius

What two structures regulate blood flow through capillaries?

smooth muscle in upstream arterioles and precapillary sphincters

What is the change in area, blood pressure, and blood flow velocity through the blood vessels?

blood pressure decreases, while blood flow velocity decreases and area increases

What are the ways of substance exchange at the capillaries?

Leaky junctions in continuous capillaries and large pores in fenestrated capillaries

Starling-Landis hypothesis is

The blood plasma loses volume in the final segments. The overall effect is a net loss (10-15%): fluid from the blood plasma tends to be transferred to the extracellular tissue fluid in a net fashion. The fluid added to the tissue fluid is picked up by the lymphatic system which ultimately returns it to the blood.

The four Starling forces are

Capillary and interstitial fluid hydrostatic pressure, osmotic force due to plasma and interstitial fluid protein concentration

Venous side of capillary 

fluid moves towards the tissue

Arteriole side of capillary

fluid reenters the capillary

Where does the lymphatic system start and where does it end?

Returns fluid that leaks out from the capillary beds. Interstitial fluid reenters the blood circulation directly at the venous end of the capillary bed and enters the lymphatic capillaries and becomes lymph. It drains into veins in the neck

How is blood pressure measured?

A stethoscope is placed on the brachial artery

What is Korotkoff's sound?

a thumping caused by a pressure wave

Pulse pressure =

Systolic Pressure – Diastolic Pressure

What is MAP? How is it calculated? What does it mean to the body?

Mean arterial pressure. It’s the pressure driving blood into the tissues averaged over the entire cardiac cycle
MAP = 2/3 DP + 1/3 SP

MAP = CO x TPR cardiac output and
total peripheral resistance (TPR)

What are the three factors that determine MAP?

Cardiac output, the total peripheral resistance and blood volume

What are the effects of epinephrine on blood vessels at different places in the body? Why are the effects different?

In the liver cell, Glycogen breaks down and glucose is released from cell. In skeletal muscle, blood vessel dilates. In cardiac muscle, blood vessel constricts. Different receptors = different effects.

How does Viagra work to dilate blood vessels?

inhibits PDE enzyme, causing accumulation of cGMP.

What is hypertension? What is the current standard for hypertension diagnosis?

High blood pressure. Defines high blood pressure to
be anyone with a systolic blood pressure (SBP) ≥ 130 mm Hg or diastolic blood pressure (DBP) ≥
80 mm Hg.

Where are the locations of blood pressure sensors? Where is the control center?

Blood pressure sensors are baroreceptors, and are located in the aorta and the brain. The control center is the medulla.

During exercise, what happens to the relative distribution and flow rate of blood? Which two organs have multiple times of blood flow volume?

redistributes blood flow by shunting it away from less active organs and directing it to working skeletal muscles and the heart to meet their increased oxygen demands.

During exercise, what are the changes in cardiac output, TPR, and MAP

CO increases, TPR decreases, MAP increases