Brainscapes- The haert Flashcards
Why do ventricles have thicker walls than the atria?
-Because they have to push blood out of the heart
-The atria push blood into the ventricles
What does the atrioventricular valve prevent and what does it link?
-Prevents blood flowing from the ventricles (when they contract) back into the atria
-Links the atria and ventricles
What does the semi-lunar valve do and what does it link?
-Stops blood flowing back into the heart when the ventricles contract
-Links ventricles, aorta and pulmonary artery
What is the function of the cords?
-Attach the atrioventricular valves to the ventricles to stop them from being forced up into the atria when the ventricles contract
Which sides pump oxygenated blood and deoxygenated blood?
Right= Deoxygenated
Left= oxygenated
Where does _____ carry blood to and from
1.Pulmenary artery
2Pulmenory vein
3.Aorta
4.Vena Cava
5.Renal artery
6.Renal vein
1.heart - lungs
2. lungs - heart
3. Heart to body
4. Body to heart
5. body- kidney
6. Kidney to vena cava
What does the blood transport?
-Respiratory gases
-Products of digestion
-Metabolic waste
-Hormones
What is the heart’s blood supply?
-Right and left coronary arteries
Relate the function to arteries
-Thick muscular walls to help the heart contract and maintain a high-pressure
-Muscular + elastcic to help stretch and recoil when the heart contracts
-The inner lining (endothelium) stretches
What is the function of arterioles?
-Aetrioles contract/ relax to allow for restriction of blood flow or full flow
What do arterioles branch into?
-Capaliries
Relate the structure of capillaries to their function
-Substances such as glucose and oxygen are exchanged between cells
-Cepillaries are always found near cells in exchnage tissues as this gives them a shorter diffusion pathway (DP)
-They are only one cell thick so decrease DP
-Lots of capillaries to increase SA for exchnage
What are capillary beds?
-Networks of capillaries throughout tissues
What is the first step of the cardiac cycle (Systole)
-Ventricles relax
-Atria contact
-Pressure in chambers increases
-Volume in chambers increases
-Blood flows into ventricles
What is the 2nd step of the cardiac cycle
-The atria relax
-Ventricles contract
-this increases pressure of the ventricles
-Forces AV to shut due to prevent backflow
-pressure higher in ventricles than pulmonary artery’s and aorta
-SL valves open
-Blood forced out of these artery’s
What is the 3rd step of cardiac cycle?
-Atria relax
-ventricles relax
-PA and A relax
-Blood flows back to the heart
-SL valves close
-Atria begins to fill gain
-Pressure is increased in atria so AV valves open
-Pressure high in VC and PV so
-Pressure of ventricles is lower than aorta and PA so AV valves open
-Blood flows passively into ventricles
What is stroke volume?
-Volume of blood pumped out with every beat (cm3)
What is tissue fluid?
-Fluid surrounding the cells in tissues
What does tissue fluid contain?
-Water
-Nuitrients
-O2
(small molecules leaving the blood plasma)
Unlike blood, what does tissue fluid not contain?
-RBC/ large proteins as they are too large to go through the capillary wall
What do cells take in from and release into tissue fluid?
Take in: O2 and nutrients
Release metabolic waste
In a capillary bed, substances move out of capillaries and into tissue fluid by what process?
-Pressure filtration
Explain how tissue fluid is formed.
-In the capillary bed, nearest the arteries, the hydrostatic pressure is greater inside the capillaries than the tissue fluid
-This means an overall force is exerted and the tissue fluid is pushed into the space surrounding cells #
-As fluid leaves the hydrostatic pressure is reduced so pressure much lower at the venule end
Why is water potential lower at the venule end than the water potential of the tissue fluid?
-Fluid loss, increasing concentration of plasma proteins
