A&P Chapter 13

Home

Get App

Create

Arteries
- Carry blood away from the heart
- Branch repeatedly & decrease in size until they become arterioles
Arterioles

Small branches off arteries that empty into capillaries
Vasomotion

Blood flow within any one capillary is intermitent rather than a steady and constant stream
Veins

vessels that collect blood from all tissues and return it to the heart
Venules

Smallest veins collect blood fr capillaries and then merge into medium sized and then lg veins
Three layers in the walls of arteries and veins
- Tunica Interna
- Tunica Media
- Tunica Externa
The walls of arteries are thicker than the walls of veins. T or F

True
Three vessels in the arterial system
- Lg elastic arteries
- Medium sized muscular arteries
- Small arterioles
What happens to the vessels as blood procedes toward the capillaries
- The number of vessels increases
- Diameter of vessels decreases and walls become thinner
What are the only vessels that allow exchange between blood and interstitial fluid?

Capillaries
Capillary Beds

Interconnected networks of capillaries
Precapillary Sphincter (band of smooth muscle)

Adjusts blood flow into each capillary
Explain pressure and valves in the vessels
- Pressure in the arterial system is high
- Pressure in veins is much lower
- Valves prevent backflow
Pressure and flow

Blood will flow from an area of higher pressure to an area of lower pressure
Circulatory pressure Vs total peripheral resistance

In order for circulation to occur circulatory pressure must higher than the resistance in the system on a whole
Blood pressure (arterial Pressure) Vs peripheral resistance (resistence of the arterial system)

For blood to flow into peripheral capillaries blood pressure (arterial pressure) must be greater than peripheral resistance (resistance of the arterial system)
What regulates BP?

Neural and hormonal ctrl mechanisms
What are the effects ventricular systole and diastole on arterial pressure?

Arterial pressure rises during systole and falls during diastole
what is the term for the difference between systolic and diastolic pressure?

Pulse pressure
What assists low pressure veins in poropelling blood toward the heart?
- Valves
- Muscular Compression
- Respiratory Pump
Homeostatic mechanisms ensure that tissue blood flow (tissue perfusion) delivers adequate ________& _______.

Oxygen and nutrients
Three things that cause variations in blood flow
- Cardiac output
- Peripheral resistance
- Blood Pressure
What are the three influences on coordinated regulation of cardiovascular function?
- Autoregulation
- Neural mechanisms
- Endocrine mechanisms
Autoregulation

Local factors that change the pattern of blood flow within capillary beds in response to chemical changes in interstitial fluids
Neural Mechanisms effect on cardiovascular function

CNS mechanisms respond to changes in arterial pressure or blood gas levels
Hormones effect on cardiovascular function
- Assist in short term adjustments such as changes in CO and peripheral resistance
- Assist in long term adjustments ie changes in blood vol that affect CO and gas transport
How is peripheral vessel resistance adjusted

By dilation or constriction of precapillary sphinters
Baroreceptor Reflexes

Autonomic reflexes that adjust cardiac output in peripheral resistance to maintain normal arterial pressures
Chemoreceptor Reflexes
- Respond to changes to the oxygen or CO2 levels in the blood or CF
- Sympathetic stimulation leads to stimulation of cardio acceletory & vasomotor ctrs
- Parasympathetic activation stimulates the cardioinhibitory ctr
Endocrine sys provides short term reg of CO and peripheral resistance with ___ & ____ that come fr the ____ ____.
- Epi
- Norepi
- Adrenal Medullae
4 hormones that have long term regulation on BP and Blood volume are
- Antidiuretic Hormone (ADH)
- Angiotensin II
- Erthropoietin (EPO)
- Atrial natriuetic peptide (ANP)
Effects of ADH
- Promote peripheral vasoconstriction
- Water and electrolyte retention
- Stimulate thirst
Efffect of angiotensin II

Peripheral vasoconstriction
Effects of Erthropoietin (EPO)

Stimulates red blood cell production
Effects of Arterial Natriuretic Peptide
- Encourages sodium and fluid loss
- Reduces BP
- Inhibits thirst
- Lowers peripheral resistance
In the body blood loss causes
- Increase cardiac output
- Mobilization of venous reserves
- Peripheral vasoconstriction
- Liberation of hormones that promote fluid retention and production of RBCs

Author

medic11

18779

Card Set

A&P Chapter 13

Description

Medic11 A&P Chapter 13

Updated

2010-05-12T13:11:35Z

Show Answers