Exam 2 Anatomy Flashcards
What is cardiac output?
The volume of blood expelled by each ventricle per minute
How do you calculate cardiac output?
Stroke volume + heart rate
What are the primary factors affecting stroke volume?
The volume in the blood before contraction “Preload”
The pressure in the arteries of the vents needs to overcome “Afterload”
What factors other than preload and afterload affect stroke volume?
Increase blood calcium
What factors affect heart rate?
Parasympathetic nervous system - Heart rate down
Sympathetic nervous system - Heart rate up
Emotions - Angry up Sad down
Body temp - Increase temp increase heart rate
Hormones and chemicals in the blood
How does thyroid hormone affect heart rate
It increases heart rate
How do potassium levels affect heart rate?
Increasing potassium levels depolarizes the plasma membrane making contraction easier to occur. Decreasing those levels does the opposite
What is cardiomyopathy?
Irreversible damage to the heart which is replaced by scar tissue. The scar tissue stretches because of high pressure in the heart. This dilates the ventricles
What are the main causes to cardiomyopathy?
1.) atherosclerosis
2.) alcoholism
How is cardiomyopathy treated?
Medication - increases the contraction strength of the heart
Heart transplant
Ventricular assistive devices - right and left
Ventricular restoration - reshaping the heart
Cellular cardiomyoplasty - using stem cells to repair the heart
Laser therapy - holes in the heart that create new vessels
Enhanced External Counterpulsation - Pumps blood back up to the heart to heavily reoxygenate
ECMO (extra-corporeal membrane oxygenation) - similar to vent assist where oxygenation occurs completely externally
What are the three layers of arteries and veins?
The tunica interna/intima
Tunica media
Tunica externa
What layer are the smooth muscles located in in vessels?
the tunica media
What innervates smooth muscle in vessels?
The sympathetic nervous system
What is the tunica interna made of?
Simple squamous epithelium (endothelium) and a thin basement membrane of connective tissue
What is the blood-filled area of all vessels called?
The lumen
What is the tunica externa made of?
Dense connective tissue which provides support and protection
What are the three types of arteries?
Elastic (conducting) arteries
Muscular arteries
Arterioles
What is the significance of elastic (conducting) arteries?
They can stretch more because the tunica media has less smooth muscle tissue and more elastic connective tissue. This is important because it prevents blood pressure from rapidly changing with each heart beat.
What is the significance of muscular arteries?
The tunica media has less elastic CT and more smooth muscle. This allows them to regulate blood flow to different body regions
What is the significance of arterioles?
They are the smallest arteries that branch off into capillary beds. They have both endothelium and smooth muscle fibers.
What is the function of a precapillary sphincter?
They contract or relax to control blood flow to regions. This allows them to give oxygenated blood to the regions that need them.
What is a capillary?
The smallest vessel
What are the three types of capillaries?
Continuous capillaries
Fenestrated capillaries
Discontinuous capillaries (sinusoids)
What is a continuous capillary?
A capillary with very little gaps so nothing can pass through the capillary walls
What is a fenestrated capillary?
A capillary with small openings in walls which allow small things to pass through (except cells and large proteins)
What is a discontinuous capillary?
A capillary with very large openings that everything can pass through. They allow blood out of/in to the blood stream from places like the liver, spleen, and bone marrow.
What are the two types of veins?
Venules
Medium and large veins
What are venules?
Veins on the other end of capillary beds from arterioles made of endothelium and a small amount of smooth muscle
What is the vaso vasorum?
A capillary network that supplies cells of the tunica media and the tunica externa.
What are medium and large veins?
They are veins duh. They have valves to prevent backflow. They are made of endothelium and more smooth muscles.
How does simulation stimulation affect smooth muscle?
It causes constriction
What are venous sinuses?
Thin-walled veins that hold deoxygenated blood, like on the heart. They are more like bowls of deoxygenated blood and have no smooth muscle.
What are portal veins?
Veins that take blood from one place to another without going back to the heart. The hepatic portal vein goes from the stomach to the liver to break down nutrients.
How does skeletal muscle aid in returning blood to the heart?
It squeeze increasing pressure on the vein and pushing the blood towards the heart
How does pressure change from breathing aid in returning blood to the heart?
As you breathe in pressure in the chest decreases (with expansion), this causes the diaphragm to increase in pressure and push blood up to heart.
What is an anastomoses?
A union of 2 or more vessels the provides an alternate route in case of blockage
What are the three types of anastomoses?
Arterial anastomoses
Venous anastomoses
Arterio-venous anastomoses
How are anastomoses named?
After the combination of what each end of the connection is.
Arterial is artery-artery
Venous is vein-vein
Arterio-venous is artery-vein
What causes an aneurysm?
Atherosclerosis
High BP
Trauma
Infection
Congenital
Where are aneurysms most common
Abdominal aorta
renal arteries
Cerebroarterial circle
What are the risk factors for varicose veins?
Women
Genetic predisposition
Pregnant
Obese
Standing a lot
What are the factors affecting blood pressure/flow
Cardiac output = Heart Rate x Stroke Volume
Vessel diameter
Blood volume
Viscosity
Vessel length
How does the autonomic nervous system affect blood pressure
Sympathetic stimulation decreases smooth muscle diameter increasing blood pressure.
What does the baroreceptor reflex do?
Uses the ANS to change heart rate and vessel diameter in order to control blood pressure
What does a baroreceptor do?
Monitors blood pressure
Where are barorecptors located?
Right atrium - Returning pressure
Aorta - Max pressure
Carotid artery - Protect the brain
How does the chemoreceptor reflex work?
It monitors O2 levels via pH levels sending info to the medulla from the aortic and carotid bodies. In low O2 environments there is a high amount of CO2 and a low pH the chemoreceptor identifies this and increases heart rate increasing cardiac output
How does Oxygen affect pH
High oxygen - Higher pH
Low Oxygen - Lower pH
What are the three short term vasoconstrictors?
Endothelin
Angiotensin II
Epinephrine/Norepinephrine