C-2a Flashcards
CAPILLARIES
Number of capillaries in a specific tissue, proportional to:
Examples:
: a tissues metabolic rate
Examples
1) muscular & Nervous tissue: High metabolic rate= extensive capillary network
2) Epidermis & Cartilage: Very low metabolic rate= lack capillaries
CAPILLARY EXCHANGE
What are the substances that move between blood and the tissues?
Movement is d/t:
-gases(o2 & co2), Nutrients, metabolic waste-products
-Movement is d/t:
Simple diffusion: gases
Osmosis: water
Filtration: Molecules
Absorption: Molecules
Leaves blood=filtered, comes back in=absorption
Movement in & out of capillaries determined by:
Opposing forces occurring in the capillaries
- Osmotic Force (pressure)- Movement of (liquid/water)
- Blood pressure/hydrostatic pressure= pressure of liquid
Colloid Osmotic Pressure:
How are proteins involved:
The Pressure (force) caused by the PROTEINS found in the PLASMA fraction of blood.
- Proteins CANNOT pass thru the vascular walls(capillaries)
- Water always moves toward the area of higher concentrated solutes
- The Presence of the Proteins in plasma tends to PULL water into the capillaries by OSMOSIS (absorption)
ARTERIAL BLOOD PRESSURE:
Generated by the heart, tends to push water out of the capillaries into the tissues
Movement in & out of the Capillaries:
Force from BP?
The force from the COLLOID OSMOTIC pressure?
What is the NET:
How fluid is moved, out of what specific end:
-As blood approaches the capillaries, BP has dropped, d/t continuous dividing of vessels.
bp:37mmHg, cop:25mmHg
=+12mmHg Net movement into tissues
-Fluid is moved OUT at the PROXIMAL arterial end of the capillary termed FILTRATION
Movement in & out of the capillaries:
When blood gets to capillaries it is?
When blood gets to the capillaries BP has decreased.
-The blood volume is pushed thru multiple capillaries- NOT just 1/2 same pressure is now divided among multiple vessels
Movement in & out, @ the DISTAL end (venous) portion of the capillaries:
BP has DECREASED below the colloid osmotic pressure;bp:17, cop:25 net:(-8) into vessels
- COP remains the same (proteins to large to be filtered)
- Fluid moves back into the vessels from the tissues termed Absorption(waste products)
Very little pressure in the Venous system.
When describing blood pressure we are referring to?
Which is created by?
Systemic Arterial Blood Pressure.
Created By: Left Ventricle, pressure in systemic arteries, Not in pulmonary vessels
Arterial Blood Pressure Facts:
Maximum pressure:
Minimum pressure:
Normal BP Recorded as:
Rises and falls in a pattern corresponding to the cardiac cycle.
-SYSTOLIC=when ventricles contract (systole), pressure in arteries increase. Complete left ventricle contraction.
-Diastolic=complete left ventricle relaxation.
120/80
Formula for BP:
Formulas for each portion that make BP:
BP=Cardiac Output x Total Vascular Resistance
- Cardiac output= HR x Stroke volume
- Stroke volume= Volume of blood pumped by the left ventricle during systole.
-Vascular resistance=peripheral resistance: degree of vasoconstriction of the arterioles
When the body has changes in one or more of these factors(BP=CAxTVR); it can affect BP.
EXAMPLES
- inc. HR= inc. BP
- inc BV= inc. BP
-inc Vascons = inc BP
when one increases another must go down usually- Peripheral resistance
Factors affecting Arterial Blood pressure:
- Peripheral Resistance
- Blood Viscosity
- Blood Volume
- Heart Rate
What is Peripheral resistance?
Factors that affect peripheral resistance and what it results in?
: the friction/resistance between the blood and the internal wall of a blood vessel that DECREASES blood flow.
- BP must overcome this to maintain normal flow.
-factors that alter PR usually cause high PB.
A. vasoconstriction of vessels
1. too much Sympathetic nerve affect
2. certain substances- hormones
B. Atherosclerosis - narrowing of arteries
What is Blood Viscosity:
Property of a liquid, how easy it flows. Inc Viscosity=thickness, decrease Viscosity= more fluid like
A. Blood cells and plasma proteins increase Viscosity i.e. incr RBC production, incr protein syntheses
B. Decreased plasma levels incr viscosity
What is Blood Volume:
-equal to:
A. Number of Blood cells & plasma proteins
B. Volume of Fluid/plasma
> Any incr in total body fluid (water retention)
- incr blood volume
- this increases BP
>Any decr in Total Body Fluid (dehydration), decr blood volume, this decr BP
Heart Rate is controlled by?
- Heart has a constant level of activity
- controlled by baroreceptors (sensory receptors for pressure)
- send data to Medulla Oblongata-which contain Cardiac Control Centers
- medulla obligate then responds through ANS
Where are Baroreceptors located, and what do they do?
Responses:
- Located in Carotid sinuses and walls of the aorta.
- detect any change in BP
- Send impulses to medulla oblongata
- medulla sends signals to the Heart thru AN nerves-SYMPATHETIC / (minimal)parasympathetic
- Low BP=inc sympathetic-inc HR, inc Cardiac force
- High BP=dec sympathetic-dec HR, dec cardiac force
High BP puts you at risk for?
How many in US have high BP?
High BP was…..
- Hear disease (1st) and Stroke (3rd) leading causes of death in US.
- 1/3 adults has high BP
- was primary or contributing cause in 1/8 deaths from ALL causes
High BP AKA:
FACTS
Hypertension.
- only 10% have an identifiable cause (means no specie cause can be found in 90% of patients)
- pt. with No identifiable cause for their HBP are said to have: ESSENTIAL/PRIMARY hypertension
- pt. WITH identifiable cause for their HBP are said to have SECONDARY Hypertension i.e. kidney disease, arteriosclerosis
Essential hypertension theory:
Based on chronic stress and GENETICS
-chronic means over a long period of time-years to decades
- types of stress- good or bad
Genetics- inherited traits predisposes an individual to HBP when faced with chronic stress.
CAPILLARIES
Structure:
What they connect and diffuse to:
Structure also allows
smallest diameter, connect arterioles to venous system.
Wall is a single layer of simple squamous.
Allows diffusion from blood to tissues and visa versa Business end.
allows damage to occur frequently
CAPILLARIES:
Number of is proportional to:
Examples:
- number in a specific tissue is proportional to metabolic rate.
- Muscular & Nervous tissues= high metabolic rate=extensive capillary network.
- Epidermis & Cartilage=very low metabolic rate=low capillaries
