Anatomy- Cardiovascular System

What factors can influence the rate of electrical impulses generated in the heart?

- Drop in blood pressure - Exercise

Let's say you went from a standing position to a supine (lying down) position, measuring your heart rate and blood pressure in both positions. What changes would you expect to see in heart rate and blood pressure? Why?

A change in blood pressure heart rate would happen. A decrease in their numbers would occur . lying down increases your stroke volume and would increase vaso return giving more blood to the heart and lowering cardiac output and the lowering blood pressure.

What are the different types of vessels that make up the vascular system? In which order does blood travel through these vessels as it leaves the heart, and then returns to the heart?

Arteries (starts from largest artery; aorta) ---- Deliver Oxygen Arterioles (smaller arteries) ---- Deliver Oxygen Capillaries (Bed) ----- exchanging oxygen and carbon dioxide with cells Example: In small intestine, each villi has a capillary in it; capillaries are really everywhere throughout body Venules (smaller veins) Veins (goes into superior and inferior vena cava---largest vein)

What are the factors that affect blood pressure?

Blood Pressure=Cardiac Output x Total Peripheral Resistance Cardiac Output= amount of blood that is leaving the heart (L/min) Total Peripheral Resistance= total resistance to flow of blood in the systemic system (entire body)

What is meant by the term venous return? How would a decrease or increase in venous return affect stroke volume?

Blood returning to the heart through the veins. Increase in venous return = more blood to pump out= increase in stroke volume. Decrease in venous return= decrease in stroke volume= decrease in blood that is pumping out.

Sam the Sabre is out for a run, and his heart rate is 150 bts/min; while his stroke volume is 90mls/beat. Calculate Sam's cardiac output in L/min.

CO= 150 x 90= 13500 mL/min = 1.35 L/min

What are the equations we've gone through to find Cardiac Output and Blood Pressure?

CO= SV x HR BP= HR x SV x TRP(SNS)

What are the factors that affect cardiac output?

CO=Heart Rate x Stroke Volume Stroke Volume= amount of blood leaving heart (mL/beat)

What are the major functions of the cardiovascular system?

Delivers blood (Oxygen) to body Delivers waste (Carbon Dioxide) from body to lungs Delivers products of digestion to cells Delivers waste to be excreted

What happens to blood pressure and heart rate when going from rest to exercise? Why?

Heart rate would increase and because you are exercising contraction is happening do skeletal muscle pump is in use and due to the sns and skeletal muscle pump in use a increase in stroke in stroke volume would occur making cardiac output more. Vasodilation would occur to get more oxygen/ blood to the muscle. Vado construction happens to other places in the body to get a greater supply in that area.

What are the three major components of the cardiovascular system?

Heart, Blood Vessels, Blood

Where is an electrical impulse initiated in the heart? How does this impulse eventually lead to contraction of the ventricles?

Initiated in the SA node (right atrium)where electrical impulses are generated which then send electrical signals through the heart muscle

What are 2 unique features of cardiac muscle cells that allow the heart to contract as a unit?

Intercalated discs keep fibers together and keep communications between cells Branching fibers connecting one another

What is meant by the arterial pressure system? The venous pressure system? What would the pressure be in the aorta (approximately) vs. the pressure where the vena cava enters the right atrium?

Mean arterial pressure= average of blood pressure (systolic+dystolic)/2= mean arterial pressure Average # = (120+80)/2 = 100 Arterial pressure system= includes arteries and arterioles, high pressure system Venous pressure system= includes the veins and venules, low pressure system Pressure in aorta= 95mmHg vs. Pressure in Vena Cava/Atrium= 5mmHg Drop in blood pressure from arterioles (80mmHg) to Capillaries (30mmHg) because there are a ton of capillaries for blood to spread out Then there is really no way to get pressure back up to what is was at originally Keeps dropping--- venules (15mmHg) and then veins (10mmHg)

How is blood pressure measured? An average blood pressure reading would be 120/80mmHg. What do these numbers represent?

Measured using two numbers Systolic Blood Pressure= pressure in blood vessels when heart beats Diastolic Blood Pressure= pressure in blood vessels when heart rests between beats

Now you stand up. What changes would you expect to see in heart rate and blood pressure? Why?

One's heart rate would increase,stroke volume would decrease causing blood pressure to raise up in order to get blood to the heart, which then would most likely cause an increase in cardiac output.

What is an ECG? What is represented by the PQRST wave? What is represented by the P wave? The QRS complex? The T wave?

PQRST = one heartbeat P wave = spreading of electrical impulses across two atria, depolarization and contraction of the left and right atria QRS = Across Ventricles at AV node, depolarization and contraction of right and left ventricles (Ventricles are bigger, therefore a bigger peak) T wave = repolarization and relaxation of ventricles

When listening to the heart with a stethoscope, it makes a 'Lub-Dub' sound, sometimes referred to as Sound #1 and Sound #2. What is making these sounds?

Sound 1= two valves (pulmonary and aortic) open, two valves (tricuspid and biscuspid) shut Sound 2= two valves (pulmonary and aortic) shut, two valves (tricuspid and bicuspid) open Between Sound 1 and Sound 2= Contraction (systole), ventricles contract, blood pushes into aorta Between Sound 2 back to Sound 1= Resting/Relaxing (diastole), ventricles fill with blood

How does this impulse spread? In other words, how does depolarization happen?

Starts in the SA node (right atrium) Spreads across heart to left atrium Activates AV node (middle of heart) Goes down bundle of His (muscle between right and left ventricles) Goes down and around the bottom of both ventricles where the purkinje fibers are then depolarized Then contractions in right and left ventricles occur

Trace the pathway of blood flow through the heart, starting with the return of blood flow from the body to the heart. You can write it out, or draw a diagram.

Superior Vena Cava- Right Atrium- Tricuspid valve- Right Ventricle- Pulmonary Valve- Pulmonary Artery- Lungs- Pulmonary Vein- Left Atrium- Bicuspid Valve- Left Ventricle- Aortic Valve- Aorta

What is the effect of the sympathetic and parasympathetic nervous systems on heart rate?

Sympathetic Nervous System (SNS) releases hormones to speed up heart rate Parasympathetic Nervous System (PNS) releases hormones to slow down heart rate

What is meant by total peripheral resistance? How does vasoconstriction or vasodilation affect TPR? In which type of vessel does vasoconstriction/dilation occur?

TPR means everything but the heart, and it is the resistance to blood flow mostly in arterioles. Vasoconstriction is harder to get blood flow through and increases TPR. Vasodilation decreases TPR because it is easy for blood to flow through.

How does the body direct blood flow toward the areas that need it and away from the areas that don't?

Through the process of vasodilation and vasoconstriction

What are two ways that blood is pumped through the veins while fighting gravity?

Valves in the veins Skeletal muscle pump/smooth muscle around veins