Circulatory System

Question 1

Purpose of circulatory system and blood?

Answer 1

• Helps distribute important nutrients, hormones, and oxygen to cells that are too far away from where these important substances are obtained

Question 2

Circulation Pathways: systemic vs. pulmonary

Answer 2

• Systemic – delivers blood to all cells and carries away waste
• Pulmonary – eliminates carbon dioxide and oxygenates blood

Question 3

Evolution of system: differences between fish, amphibian, reptile and mammal

Answer 3

• Fish hearts:
  
  • ​Single circuit
  • 2 chambers – atrium and ventricle
• Amphibian hearts:
  
  • Double circuit
  • 3 chambers – 2 atria and one central ventricle
  • No septum, so deoxygenated blood and oxygenated blood mix causing heart deficiency
• Mammal hearts:
  
  • Double circuit
  • 4 chambers – 2 atria and 2 ventricles

Question 4

Chambers of heart, structure of heart tissue

Answer 4

• The top two chambers of the heart are the left and right atria (singular: atrium)
• The bottom two are the left and right ventricles
• There is a wall of muscle in between the left and right chambers of the heart called the septum, preventing oxygenated and deoxygenated blood from mixing (in mammal hearts only, not amphibian)
• Tissues:
  
  • Epithelial tissue (inner and outer)
  • Myocardium (middle layer)
  • Pericardium (outer layer)

Question 5

Pathway of blood flow through heart -path of deoxygenated and oxygenated blood

Answer 5

• Blood enters the right atrium from the superior and inferior vena cava
• Then goes through the tricuspid valve to the right ventricle
• Then it moves into the right and left pulmonary arteries to the lungs
• Oxygenated blood is returned to the heart through the pulmonary vein
• Blood flows into the left atrium, then through the bicuspid valve into the left ventricle, then into the ascending aorta
• Blood is next distributed to the rest of the body

Question 6

Cardiac cycle, systole/diastole

Answer 6

• Cardiac cycle – the sequence of events that occurs when the heart beats
• Systole is the phase of the heartbeat when the heart muscle contracts and pumps blood from the chambers into the arteries
• Diastole the phase of the heartbeat when the heart muscle relaxes and allows the chambers to fill with blood
• 1) Heart is relaxed (atrial and ventricular diastole (dub))
• 2) Atria contracts (atrial systole, ventricular diastole)
• 3) Ventricles contract (ventricular systole, atrial diastole (lub))

Question 7

SA node (pacemaker), AV node, and role in regulation of heartbeat

Answer 7

• The SA node / sinoatrial node: it sends electrochemical signals to the atria to contract
• The AV node / atrioventricular node: it sends electrochemical signals to the ventricles to contract after delaying the signal from the SA node

Question 8

Names of blood vessels connected to heart and heart valves

Answer 8

• Aorta
• Pulmonary artery
• Pulmonary veins
• Inferior and superior venae cavae

Question 9

What does an EKG (or ECG) measure?

Answer 9

• Measures the electrical activity of a heartbeat
• It lets people know if parts of the heart are too large, or overworked

Question 10

Capillaries

Answer 10

• Any of the fine branching blood vessels that form a network between the arterioles and venules
• Made of endothelial cells only

Question 11

Arteries

Answer 11

• Carry blood to the heart, and capillaries
• Thickest, most elastic walls because of high pressure
• Carry O2-rich blood except for pulmonary artery
• Smallest arteries are arterioles (Largest = aorta)

Question 12

Vein

Answer 12

• Walls thinner, less elastic, very low blood pressure (near 0)
• Carry Carry O2-poor blood except for pulmonary vein
• Veins have valves to prevent backflow
• Smallest veins are venules

Question 13

How are capillaries structured to allow for rapid diffusion of nutrients and waste between the circ system and cells/tissues of body?

Answer 13

• They are structured like a net and thin enough to allow chemical exchange, dispersing nutrients throughout the circulatory system

Question 14

Blood pressure and velocity through different blood vessels

Answer 14

• The force blood exerts against the wall of a vessel
• Rises as we age

Question 15

Measurement of blood pressure (sphygmomanometer use and function)

Effects of hypertension (and low blood pressure)

Answer 15

• A cuff is placed around someone’s arm, and systolic pressure is measured when blood in arteries is able to push through the arm in spurts with the cuff on
• When blood flows continuously through the artery, the diastolic pressure is taken
  *

Question 16

Atherosclerosis

Answer 16

• Plaques develop on the inner walls of arteries, narrowing the passageway (resulting in increased blood pressure)
• Thickening & hardening of arteries due to fatty deposits on artery wall, causing narrowing of arteries & thus diminished blood supply

Question 17

Hypertension

Answer 17

• Blood vessels constantly constricted – diameter decreases, pressure increases
• High blood pressure, heart works harder and causes ruptures in arterial walls, causing plaque buildup
• Causes cardiovascular diseases

Question 18

Angina pectoris

Answer 18

• Chest pain caused by reduced flow of blood in the heart due to coronary heart disease

Question 19

Coronary thrombosis

Answer 19

• Blockage of blood flow to heart due to blood clot in an artery
• Can lead to myocardial infarction

Question 20

Myocardial infarction

Answer 20

• ‘Heart attack’, death of heart muscle tissue due to lack of oxygen supply

Question 21

Stroke

Answer 21

• Death of brain tissue resulting from blockage of arteries/blood flow to the brain

Question 22

Heart failure

Answer 22

• The heart cannot pump enough blood to supply the body with

Question 23

Cardiovascular disease risk factors

Answer 23

• Lifestyle/behavioral change:
  
  • ​Regular exercise, monitor stress, added fruits & vegetables to diet
• Limit saturated fat intake:
  
  • Quit smoking, etc
• Medication (blood pressure, cholesterol):
  
  • Some medications decrease blood pressure and cholesterol
• Angiography (for diagnosis):
  
  • Used to see inside blood vessels inside the body
• Cardiac bypass surgery:
  
  • ​Restores normal blood flow to an obstructed coronary artery by creating a new passageway
• Angioplasty:
  
  • Inserting a tiny inflatable balloon to compress plaques
• Stent placement:
  
  • A small metal mesh tube that keeps arteries open.

Question 24

Blood makeup and function (4)

Answer 24

• Plasma
  
  • ​Transports nutrients and proteins, suspends white and red blood cells.
• WBC’s
  
  • ​Help fight infections, (white blood cells)
• RBC’s
  
  • ​Deliver oxygen to cells and dispose of carbon dioxide (red blood cells).
• Platelets
  
  • ​Cell fragments in the blood that help blood clot after an injury.

Question 25

What are: arrhythmia, heart murmur

Answer 25

* **Arrhythmia** is irregular beating of the heart * **Heart murmur** is when a stream of blood squirts backward through a valve