Vessels activity

Vessels

Arteries, capillaries, and veins

• Walls composed of three layers called tunics

Arteries

Branch into smaller vessels, extending from the heart

• Decrease in lumen diameter and elastic fibers

• Increase in relative amount of smooth

  
  

3 types of arteries

Elastic, muscular, and arterioles

Capillaries

All vessels connecting arterioles to venules

• 1 mm in length

• dilated 8-10 micrometers

• Endothelial wall on basement membrane

3 types of capillaries

Continuous, fenestrated, and sinusoid

Veins

high

• Venules; the smallest with diameter of 8-100 micrometers

• smallest have postcapillary venules

Tunics

Vessel walls are composed of three ___?

Tunica Intima

first layer made out of simple squamous epithelium

• subendothelial layer containing areolar connective tissue

Tunica media

Secondary layer, composed of smooth muscle cells and elastic fibers

Tunica externa

Third layer containing areolar connective tissue made up of elastic and collagen fibers

• may contain vaso vasorum

Vasa vorum

Supplies blood to large vessels

Three vessel types

Arteries, veins, and capillaries

Arteries

Which vessel has the thickest tunica media?

Elastic arteries

Largest arteries that conduct blood from the heart to the muscular arteries

• Has several layers of elastic fibers which allows the vessel wall to recoil after stretch

Types of elastic arteries

Aorta, pulmonary trunk, common carotid, and common iliac

Muscular arteries

Medium arteries that distribute blood to specific body regions that are named for what they “feed”

• 2 elastic tissue layers

Internal and external elastic lamina

Two elastic tissue layers of muscular arteries

Brachial and coronary

Two examples of muscular arteries

Arterial artery

Smallest arteries usually slightly constricted

• Vasomotor tone

• primary regulators of blood pressure and blood flow

Vasomotor tone

maintained by continuous sympathetic stimulation

Maintaining forward blood movement between ventricular contractions

A patient has a disorder that substantially reduces the elasticity of the aortic wall. The left ventricle can still eject blood into the aorta normally. Which function of the aorta would be most directly impaired?

Continuous capillary

Tight junctions with small gaps that allow glucose in

Fenestrated capillary

endothelial cells that have pores which allow movement of smaller plasma proteins

• found in areas with lots of fluid

• kidneys capillaries: blood to urine

• intestines capillaries absorbing nutrient

Sinusadal capillary

Endothelium and basement membrane that transports large substances

• located in bone marrow and spleen

Metarteriole, Throughfare channel, and Postcapillary venule

When all pre-capillary sphincters are contracted, which of the following capillary bed structures will still receive blood flow?

Venules

Which of the following merge to form veins?

Preventing retrograde blood flow towards the feet

A 62-year-old patient has damaged valves in several veins of the lower leg. When standing for long periods, blood tends to accumulate in the affected veins. Which normal function has been most directly compromised?

Elastic

In which artery type, would you expect to have the greatest pressure?

• artery closest to heart

40

A patient has a blood pressure of 120/80. What is the patient’s pulse pressure?

Blood viscosity

A cyclist uses blood doping to try improving their cardiovascular endurance. What would be the impact on the following sources of resistance?

Relaxation of smooth muscle in the tunica media of arterioles

A 20-year-old developed a severe allergic reaction after eating peanuts. Widespread vasodilation causes his blood pressure to fall rapidly. Which change in the blood vessels is most directly responsible for the decrease in the vascular resistance?

5 mm long with diameter of 1.0 mm and normal blood viscosity

Which of the following vessels below would you expect to have the least resistance?

Movement through intercellular clefts

Water soluble substances would most likely be transported into a continuous capillary via which of the following transport mechanisms?

Bulk flow

Fluid force out of capillary clefts at arterial end & returns to blood at the venous end

Decreased colloid osmotic pressure

Liver cirrhosis causes a decrease in plasma protein production. Which of the following would you expect as a result?

Edema

abnormal accumulation of excess fluid in interstitial spaces, which causes swelling

Heart failure or blockage in lymphatic vessels

Which could be to blame for the development of edema?

Total peripheral resistance & pressure gradient

Blood flow is impacted by what two factors?

Skeletal muscle pump, valves, and respiratory pump

The pressure gradient in veins is low and non-pulsatile, but the cardiovascular system is a circuit that depends on venous return. What features allow the low pressure venous system to return blood to the heart?

Skeletal muscle pump

Muscle contraction squeezes veins and encourages blood return from limbs

Valves

Prevents backflow and moves blood in uni-directional movement, Blood will not regenerate to our feet.

Respiratory pump

Inspiration causes increased abdomen pressure and decreased thoracic pressure, so abdomen blood moves to the thoracic cavity.

Epinephrine, Norepinephrine, and Angiotensin II

short term regulators of blood pressure

Epinephrine

Hormone release from the adrenal gland that causes cardiac output and vasoconstriction.

Angiotensin II

Adrenal gland hormone that stimulates vasoconstriction, reduces urine output, and stimulates thirst

Vasodilation of the arterial vessels which results in a decreased sympathetic tone

Skeletal muscles release high amounts of CO2 in H+. This will cause?

Brain and kidneys

Which organs do not have increased blood flow during exercise