Blood vessels: Plumbing of the people

Chapter 20A&P

Types of Blood VesselsArteryArterioleCapillaryVenulesVeins

• Stretch out for 100,000 km or 60,000 miles!

Structure of Blood Vessel Consists of three layers:1. Tunica adventitia/externa-

“coming from outside”; outermost layer; fibrous connective tissue; prevents tearing

2. Tunica media- “middle coat”; smooth muscle tissue and elastic tissue; change b.v. diameter

3. Tunica intima/interna- “innermost coat”; endothelium tissue; smooth lining; helps make up semilunar valves in veins

Lumen – central blood-containing space

1. Arteries distribute; use precapillary sphincters to regulate flow

2. Capillaries transport essential materials to and from cells by diffusion

3. Veins collect; use capacitance or stretch to catch all blood; sinuses- reservoirs of blood

Blood vessel structure

Arteries: Close Up

Blood pressure: Hydrostatic force that blood exerts against the wall of a vessel

1.Arterial blood pressure- highest; from cardiac output (heart rate & contractions) and peripheral resistance (blood viscosity & diameter of arterioles)

2.Capillary blood pressure- lowest; thin walls for diffusion and filtration

3. Venous blood pressure- medium; from pressure gradient of skeletal muscle contractions & total blood volume

Nervous Control of CV System

Circulation Routes:1. Systemic- WHOLE BODY; blood flow from left ventricle to all parts of

body and back to right atrium2.Pulmonary- LUNGS; blood flow from right ventricle to lungs, get O2,

release CO2, and go back to left atrium3.Hepatic Portal- DIGESTION; blood flow from digestive organs into

liver 1st through hepatic portal vein blood leaves liver through hepatic vein into inferior vena cava. Liver can remove excess glucose and store it as glycogen; also it can detoxify blood (alcohol).

4.Fetal- FETUS; gets O2 and food through diffusion from mother’s blood and receives it from placenta through umbilical arteries and veins; ductus venosus allows blood to by-pass fetal liver; also by-passes lungs; foramen ovale opens from right atrium into left atrium in septum; ductus arteriosus lets blood enter aorta from pulmonary artery; No maternal blood actually mixes with the fetus. After birth, lungs function and extra vessels are not needed.

Circulation Routes

1. Systemic- WHOLE BODY; blood flow from left ventricle to all parts of body and back to right atrium

Circulation Routes

2.Pulmonary- LUNGS; blood flow from right ventricle to lungs, get O2, release CO2, and go back to left atrium

Circulation Routes 3.Hepatic Portal-DIGESTION• blood flow from digestive organs into liver 1st

through hepatic portal vein blood leaves liver through hepatic vein into inferior vena cava.

• Liver can remove excess glucose and store it as glycogen; also it can detoxify blood (alcohol).

Circulation Routes

4.Fetal- FETUS• gets O2 and food through

diffusion from mother’s blood and receives it from placenta through umbilical arteries and veins

• ductus venosus allows blood to by-pass fetal liver; also by-passes lungs

• foramen ovale opens from right atrium into left atrium in septum

• ductus arteriosus lets blood enter aorta from pulmonary artery

• No maternal blood actually mixes with the fetus

• After birth, lungs function and extra vessels are not needed.

The aorta branches into 3 main arteries:

1. Brachiocephalic

2. Subclavian

3. Carotid

VI. Blood vessels of the body

Arteries: Veins:

Carotids – C, I, E Jugular – I, E

Brachiocephalic Brachiocephalic – R, L

Abdominal aorta Vena Cava – I, S

Iliac – C, I, E Iliac – C, E

Femoral Femoral

Popliteal Popliteal

Arcuate Dorsal venous arch

Subclavian – R, L Subclavian – R, L

Aorta Hepatic Portal/ Hepatic

Palmar arch Digital

Pulmonary Pulmonary

Plantar arch Plantar arch

Splenic Splenic

Renal Renal

Axillary Axillary

Mesenteric – S, I Mesenteric – S, I

Tibial – A, P Tibial – A, P

Brachial Brachial

Radial Radial

Ulnar Ulnar

Coronary Coronary

Arterial System

Venous System