Circulation Test Review Flashcards
To learn how blood circulates in our body (15 cards)
Name 3 differences between arteries and veins?
Arteries:
- Thick muscle layer
- No valves
- Movement of blood by Vessel walls contracting
Veins:
- Thin muscle layers
- Valves
- Movement of blood by contraction of skeletal muscles
Why do capillaries need to be so thin?
Blood capillaries are a single layer so oxygen and nutrients can easily diffuse across their walls into the tissue; same as CO2 and waste
Why do blood velocity and blood pressure rise and fall in arteries?
Both blood and velocity rise when ventricles contract, and both fall when ventricles relax
What two fetal structures allow most of the blood to by-pass the lungs? Why is blood flow to the lungs not necessary in the fetus?
- Arterial duct
- Oval opening
The fetus receives oxygen and gets rid of CO2 at the placenta instead of the lungs
When the atria are contracting, what two things are the ventricles doing?
The ventricles are relaxing and filling with blood
Will the heart beat independently of the nervous system? Explain.
Yes because the heart has two nodes: the SA node and the AV node which cause the atria and ventricles to contract
Why does reading of blood pressure include two numbers?
120/ 80
Systolic B.P/ Diastolic B.P
What is the main cause of high blood pressure? Of low blood pressure?
High blood pressure (Hypertension):
- Atherosclerosis
- Narrowing of the arteries
Low blood pressure (Hypotension):
-Dehydration
Explain how arterioles help to:
a) Regulate body temperature
b) Direct more blood to the intestines after a meal
a) Sphincters in arterioles will relax, allowing more blood flow to arms and legs thus increasing the body temperature. The sphincters will then contract, lessening blood flow thus decreasing the body temperature.
b) Sphincters in the arterioles will relax to allow more blood flow to the intestines after a meal. More blood flow to the intestines than muscles at this time
Describe the structures and functions of the:
a) Lymph veins
b) Lymph capillaries
c) Lymph nodes
a) Lymph veins are similar to veins, containing valves
- Collects lymph from many lymph capillaries and return it to the blood arm veins
b) Lymph capillaries are thin, narrow tubes
- Take out excess fluid that has not entered the blood stream
c) Lymph nodes are hollow structures containing WBC
- Clean and filter the lymph
List the structures, in order, that impulses travel through during one cardiac cycle?
SA node -> Atria -> AV node -> AV bundle (in septum) -> Purkinje fibers (in walls of ventricles)
In which organ would an embolus (travelling blood clot) lodge if it is formed in the:
a) Hepatic-portal vein
b) Renal artery
c) Iliac vein
Note: The embolus would lodge in the first capillary bed that it encounters
a) Liver
b) Kidney
c) Lungs
The major systemic artery in the blood is ____
Aorta
Why do capillaries have walls that are single-cell layers?
- Faster gas exchange (O2,CO2)
- White blood cells have to leave capillary to infection site
What happens if SA nodes don’t function properly?
- Uncontrolled blood pumping
- Un-rythmic beats
