11.3 Blood vessels Flashcards
What are blood vessels
(What are the different types of blood vessels)
Blood vessels are a complex networks of tubes that branch and rebranch
Many types of blood vessels
Aorta –> arteries – arterioles (TYPES OF ARTERIES)
Venca cava –> Veins –> Venules (Types of veins)
Cappiliaries
What are arteries?
- What type of blood does it carry, where does it deliver to?
- Exception?
What is its struction?
WHen the heart contracts and relaxes what does it do?
Type of blood vesse that carries blood away from the heart (A for away)
–> Usually carries oxygenated blood (because it carries blood away from the heart to the body to deliver oxygen)
–> EXCEPTION IS PULMONARY ARTERY (Deoxygenated blood to the lungs)
Made of:
1) 3 layers of tissues
2) Outer layer: elastin fibres
Elasticity allows artery walls to expand and contract, helping to pump blood
heart contracts: they expand
heart relaxes: they return to original size
*The pulse we can feel is expansion of larger arteries close to the skin
What are aterioles?
-> What is its made out (note that aterioles and arteries are made out of the same thing) of and how does it work (to move the blood/what is bloodmovement controlled by)?
A type of artery,
arteries turn into smaller blood vessels called arterioles
Arteries lead to cappiliaries.
Therefore arterioles control blood flow into capillaries
Nerve impulses cause the smooth muscle (Muscle that is involuntary) (Nervous systyen controls the arteries to contract or relax).
–> Controlling blood flow leads to temperature (vasodilation and vasoconstriction)
Flow chart of arteries (largest to smallest)
Aorta –> Arteries –> Arteroles (AWAY)
what are capillaries?
–> Function?
4 features that make them good
The smallest type of blood vessel.
–> Receives blood from arterioles.
–> Because so small there is an abundant of them, and they form a network of blood vessels that supply oxygen and nutrients to every cell.
THE SITE OF GAS EXCHANGE AND NUTRIENTS EXCHANGE.
1) Very small (smaller diameter)
2) Very thin, 1 cell layer thick
3) RBC travels in a straight line
4) No body cell is 2 cells away from capilliaries.
–> Blood has a significant decrease in pressure when they enter the capillaries.
What is the aorta?
The largest artery in the body, carries oxygenated blood from the heart to the body
—> Branches to majour arteries that link to other places
–> Receives blood from the left ventricle.
Why do capilliaries not have high blood pressure if they are so small? Why?
MIllions of capillaries = larger total cross section
–> Resulting in decreased blood pressure (From a river to many small streams)
Significant decrease in the rate at which the blood flows through capillaries (allows time for diffusion)
What is the structure of a capilliary?
Arteries and veins merge in a mirror image
Arteries –> Ateriole –> Capillary –> Venule —> Veins
No smooth muscle = cannot be controlled by the nervous system
–> Controlled by pre-capillary sphincters (Located at the branch, between the arterole and the capilliary)
—> Contract and relax to push blood flow
How do capillairies do gas exchange and nutrients exchange
Gas exchange = diffusion down the concentration gradient.
Nutrient exchange = pressure differences and water concentration differences.
How does blood flow in arterioles, beyond the smooth muscle?
-Temperature places a big role.
Losing heat = Vasodialation (Low blood pressure)
Reataining heat = Vasoconstruction (High blood pressure)
How does does vasodialation work?
-> Increasing the diameter of arterioles (dialation) = increase in blood flow.
However by increasing the diameter you lower blood pressure.
—> Used as a cooling stadgey/ because blood regulates body
1) Environment is hot
2) Nerve impules cause smooth muslces to contract
3) Body relaxes (dialates)
4) Bigger dialation = increased blood flow (Causing you too look more flushed)
5) Increased bood flow to the skin = blood is closer to its environment, and the environment can talk body heat
What is vasoconstruction?
The decrease in diameter of the arterioles.
–> Decreasing blood flow, but because the diameter decreases it means theres less volumn in the arterioles and therefore it can lead to high blood pressure
1) environemt is cold, body is rapidly looking heat
2) Nerve implushes contract smooth muscles to contract
3) Contraction = narrowing diameter (Arterioles are clenching)
4) Small blood flow = leess blood flow to the indivduals own epitheial cells.
What are the two main points/seeings you can take your pulse?
Radial Artery
Carotid Artery
What is the relationship between pulse rate and exercise? Why does this occur?
Increased excersize = increased pulse
Increased excersize requires more energy, more cellular respiration makes create ATP molecules = more oxygen needed
Why do you think the radial artery is the most commonly used pulse point?
least invasive, other arteries are deeper to get through therefore these are easier to detect your heart beats easiest to maintain in contact for long periods of time