circulatory system

What is homeostasis?

• A process by which a constant internal environment is maintained despite the changes in the internal and external environment

• The cells of each organ depend on the activities of all other organs, and only through a system of nerve impulses, or hormones, can the the activities of each organ influence the internal environment of the entire body

The main functions of the circulatory system include:

• delivers oxygen nutrients, Hormones, and waste around the body

• Distributes heat around the body

3 components of all circulatory systems:

• a fluid to circulate and transport materials

• A network of tubes for the fluid to flow

• A pump that pushes the fluid through

What is the difference between an open and closed circulatory system

Open - a fluid is pumped into body cavities/sinuses, where it flows directly over cells, fluid is hemolymph

Closed - fluid (blood) contained in a series of tubes and vessels

What is difference between pulmonary and systemic circuit

Pulmonary: heart → lungs → back to heart

Systemic: heart → rest of body → back to heart

What is diastole

Ventricular relaxation stage of the cardiac cycle

What is systole

Ventricular contraction stage of cardiac cycle

What is the sinoatrial (SA) node

• pacemaker

• Bundle of specialized nerve and muscle cells located at the junction of the superior vena and right atrium

• Can initiate electrical impulses spontaneously

What is the atrioventricular (AV) node

• Modified cardiac muscle cells located mass between the right atrium and right ventricle

• Serves as a conductor of nerve impulses

What happens during diastole?

• atria contracted, ventricles relaxed

1. SA node initiates nerve impulses that are sent across atria walls (L & R)

2. Atria contract in unison, pushing blood through the AV valves to the ventricles

3. The spreading nerve impulses reach and trigger AV node, which in turn stimulate the bundle of His

What is bundle of His

Modified muscle fibres in septum

What happens during systole

• atria relaxed, ventricles contracted

1. Bundle of His stimulates the left and right lurking fibres of ventricles

2. Causing ventricles to contract from the bottom-up, pushing blood through the semi-lunar valves

3. Back to diastole

What is pericardium

• The sac that is made of epithelial and fibrous tissue covering the heart

• The contains fluid to reduce friction as the heart beats

What causes the heart sounds

caused by the closing of the heart valves

What is the LUBB caused by

The AV valves closing because of the back pressure of the blood created as the ventricles fill up and contract

what is the DUBB caused by

The semi lunar valves closing by the backflow of the blood in the aorta & pulmonary arteries AFTER the ventricles have contracted

What is the P, QRS, and T wave seen on an ECG/EKG

• P wave - atrial contraction

• QRS wave - ventricular contraction

• T wave ventricular recovery (i.e. relaxation)

What is arrhythmia

Too fast, too slow or irregular heartbeats

What is ventricular fribilliation

Uncontrolled contraction of ventricles; erratic electrical impulses; the ventricles to quiver uselessly, instead of pumping blood’ blood pressure drops, cutting off blood supply to vital organs; frequently triggered by a heart attack

What is heart murmur

The sound made by blood as it is forced back through a damaged valve that doesn’t work properly, the heart of individuals with heart murmurs will compensate for decreased oxygen by beating faster

Describe flow of blood through the heart: in order

1. Superior and inferior vena cava

2. Right atrium

3. Atrioventricular valve (tricuspid valve)

4. Right ventricle

5. Right and left pulmonary arteries

6. Right Semilunar valve

7. Lungs

8. Left and right pulmonary veins

9. Left atrium

10. Atrioventricular valve (Bicuspid valve)

11. Left ventricle

12. Semilunar valve

13. Aorta

What is the wall separating the right and left sides of the heart

septum

What is the structure of arteries

• endothelial lining

• Smooth muscles (thick)

• Outer fibrous coat

What is the structure of veins

• endothelial lining

• Smooth muscles.(thin)

• Outer fibrous coat

• Veins have a valve (preventing backflow)

Structure of capillaries

• endothelial cell

• Mitochondria

• Nucleus of endothelial cell

How does the heart muscle gets its nutrients from

• the coronary blood vessels

• Aorta → coronary arteries → cardiac cells

Systolic blood pressure

Pressure exerted by blood on the arteries during ventricular contraction

Diastolic blood pressure

Pressure exerted by blood on the arteries during ventricular during ventricular relaxation/filling

What are 6 things that blood transport around the body

• oxygen

• Nutrients

• Waste

• Hormones

• Heat

• Immune cells and antibodies (white blood cells)

arteriolar resistance

the opposition to blood flow in the arteries

• increase blood flow to the capillaries

• increase blood in the arteries

• blood pressure drops/decreases

arteriolar dilation

the widening of the arterioles caused by relaxation of smooth muscle in their walls

• decrease blood flow to the capillaries

• decrease blood in the arteries

• blood pressure increase

capillaries

• the smallest blood vessels

• bridge between arteries and veins

• one cell thin walls to allow a single red blood cell through

  • exchange of oxygen, nutrients, and waste

arterioles

a small branch of artery leading to the capillaries

3 types of arrhythmais

• tachycardia - rapid heart rate, increased risk of stroke, or cause sudden cardiac arrest/death

• ventricular fibrillation - uncontrolled contraction of ventricles, erratic electrical impulses (from sinoatrial node), blood pressure drops, cuttin goff blood to vital organs

• heart murmur - the sound made by blood as it is forced back through a damaged valve (underdeveloped or not work properly)

what is stoke volume

volume of blood pumped during each cycle/heartbeat

cardiac output

amount of blood pumped from the heart each minute

blood pressure

force of the blood on the walls of the arteries

factors affecting blood pressure

1. heart rate - increase in heartrate causes increase in blood pressure

2. size of arteries - as diameter of arteries increase, BP will decrease, vise versa

3. blood volume - increase in amount of blood will increase BP, vise versa

4. elasticity - as elasticity of blood vessels decrease, blood pressure increases

5. viscosity - the thicker the blood, the more resisence to flow, so BP increases