Ch 21 blood

Elastic rebound

Arterial walls Stretch during systole Keep blood moving during diastole by returning to orignal size

Cardiovascular (CV) center of the medulla oblongata

Consists of cardiac centers and vasomotor center

Mean arterial pressure (MAP)

Diastolic pressure + one-third pulse pressure

Pulse pressure

Difference between systolic and diastolic pressure

Filtration

Driven by hydrostatic pressure Water and small solutes forced through capillary wall Leaves larger solutes in bloodstream Generally occurs on arteriole end

Vascular resistance

Due to friction between blood and vessel walls Depends on vessel length and vessel diameter

Decrease, increasing

During hemorrhaging, the drop in capillary hydrostatic pressure will ________ NFP, thus ________ reabsorption.

Internal elastic membrane (in arteries)

Elastic fibers in outer margin of tunica intima

Venous valves

Folds of tunica intima Prevent blood from flowing backward Compression of veins pushes blood toward heart

Flow is proportional to the pressure gradient divided by resistance

Formula for flow

NFP = (CHP- IHP) - (BCOP-ICOP)

Formula for net filtration pressure

Continuous capillaries

Found in all tissues except epithelia and cartilage Permit diffusion of water, small solutes, and lipid- soluble materials

Precapillary sphincter

Guards entrance to each capillary Opens and closes, causing capillary blood to flow in pulses

Sinusoids (sinusoidal capillaries)

Have gaps between adjacent endothelial cells Permit free exchange of water and large plasma proteins Found in Liver Spleen Bone marrow Endocrine organs

Arterioles

Have little or no tunica externa Have thin or incomplete tunica media

Common carotid

Identify the arteries labeled "9."

Brachiocephalic trunk

Identify the artery labeled "1."

Subclavian

Identify the artery labeled "10."

Inferior mesenteric

Identify the artery labeled "16."

Common iliac

Identify the artery labeled "6."

Inferior vena cava

Identify the vein labeled "10."

Median cubital

Identify the vein labeled "12."

External iliac

Identify the vein labeled "6."

Brachiocephalic

Identify the vein labeled "8."

Brachial

Identify the vein labeled "9."

D) a vessel 1.0 cm in diameter and 2 meters long

In which of the following would the blood flow be highest? A) a vessel 0.5 cm in diameter and 2 meters long B) a vessel 1.0 cm in diameter and 10 meters long C) a vessel 0.5 cm in diameter and 4 meters long D) a vessel 1.0 cm in diameter and 2 meters long

Tunica intima (inner layer)

Includes The endothelial lining Connective tissue layer Internal elastic membrane (in arteries)

Net filtration pressure (NFP)

The difference between Net hydrostatic pressure Net osmotic pressure

Hydrostatic, colloid osmotic

The force that moves fluid out of capillaries is ________ pressure whereas the opposing force that moves fluid into capillaries is ________ pressure.

external elastic membrane.

The layer between the tunica media and the tunica externa in a large artery is the

Arterioles

The main control of peripheral resistance occurs in the

Reabsorption

The result of osmosis Higher solute concentration leads to higher osmotic pressure (OP) of a solution Gernerally occurs on venule end

- Arteries have thicker walls and higher blood pressure than veins - A constricted artery has a small, round lumen - A vein has a large, irregular lumen - The endothelium of a constricted artery is folded -Arteries are more elastic than veins - Veins have valves

- Differences between arteries and veins

Aneurysm

A bulge in an arterial wall Caused by weak spot in elastic fibers Pressure may rupture vessel

Hypertension

Abnormally high blood pressure Greater than 140/90

Hypotension

Abnormally low blood pressure Can lead to fainting

Autoregulation of blood flow within tissues

Adjusted by peripheral resistance while cardiac output stays the same Precapillary sphincters are stimulated to constrict or dilate, altering blood flow

Tunica externa (outer layer)

Anchors vessel to adjacent tissues

Blood pressure (BP)

Arterial pressure (mm Hg)

15, filtration

Calculate the net filtration pressure (NFP) with a blood hydrostatic pressure of 40 mm Hg and a blood colloid osmotic pressure of 25 mm Hg. Then determine if filtration or reabsorption occurs. NFP = ________ and results in a fluid ________.

Blood colloid osmotic pressure (BCOP)

Caused by suspended blood proteins that are too large to cross capillary walls

total peripheral resistance

Circulatory pressure Must overcome affected by Vascular resistance Blood viscosity Turbulence

Edema

May occur when the plasma concentration of protein is reduced, capillary hydrostatic pressure is elevated, and the capillary endothelium permeability goes up.

-Systolic pressure

Peak arterial pressure during ventricular systole

Chemoreceptor reflexes

Peripheral chemoreceptors in carotid bodies and aortic bodies monitor blood changes in pH, O2 and CO2 Coordinate cardiovascular and respiratory activities

Fenestrated capillaries

Permit rapid exchange of water and larger solutes Found in Choroid plexus Endocrine organs Kidneys Intestinal tract

Venous pressure

Pressure in the venous system

Capillary hydrostatic pressure (CHP)

Pressure within the capillary beds

Antidiuretic hormone (ADH)

Released by neurohypophysis (posterior lobe pituitary) Elevates blood pressure Reduces water loss at kidneys

Angiotensin II

Released in response to a decrease in renal blood pressure Stimulates Aldosterone production ADH secretion Thirst Cardiac output and peripheral vasoconstriction

Natriuretic peptides

Respond to excessive diastolic stretching Reduce blood volume and blood pressure by several means

Vasa vasorum ("vessels of vessels'

Small arteries and veins in walls of large arteries and veins Serve cells of tunica media and tunica externa

Baroreceptor reflexes

Stretch receptors in walls of Carotid sinuses (maintain blood flow to brain) Aortic sinuses (monitor start of systemic circuit) Right atrium (monitors end of systemic circuit)

varicose veins, hemorrhoids

When walls of veins near the valves weaken,______________ or ______________ may result

Veins, they can stretch (capacitance)

Where is the majority of blood found? Why?

Tunica media

Which layer of a blood vessel contains concentric sheets of smooth muscle tissue?

-Diastolic pressure

• Minimum arterial pressure at end of ventricular diastole

respiratory pump

• Thoracic cavity expands during inhalation, decreasing venous pressure in the chest