Heart and blood vessels

Question 1

What is the function of a cardiovascular system, and is it necessary for life?

Answer 1

A network of organs and vessels that transport nutrients, oxygen, and blood

  - Made up of heart and blood vessels 
  - Two distinct LOOPS (one to carry deoxygenated blood and other to carry oxygenated blood)

Function of the cardiovascular system is to move oxygenated blood throughout the body and send deoxygenated blood back to the lungs

Not all organisms need a circulatory system → some can use this method ^ to exchange gasses across the membrane `

Question 2

Open system

Answer 2

heart, vessels, and blood BUT vessels spill content out into body
Eg. worms that use simple diffusion to exchange gasses across the cell membrane

Question 3

closed system

Answer 3

vessels never spill out, but constrict to let gasses escape
Eg. Humans

Question 4

Why does the human heart have four chambers?

Answer 4

We are big and have fast metabolisms that require more oxygen

Question 5

Path of deoxygenated blood

Answer 5

Inferior vena cava → Right atrium → tricuspid valve → right ventricle → pulmonary valve → pulmonary artery → Lungs

Question 6

Path of oxygenated blood

Answer 6

Lungs → pulmonary vein → left atrium → mitral valve → left ventricle → aortic valve → aorta

Question 7

What is cardiovascular disease (CVD)?

Answer 7

Group of disorders of the heart and blood vessels referred to as heart disease and stroke

Question 8

What causes heart attacks and strokes? What are some of the risk factors for CVD?

Answer 8

1. Heart attacks are caused by a blockage of the coronary arteries. When the heart doesn’t receive oxygen due to a blockage in the artery it can cause some of the muscle cells to begin to die, what is called a myrocardial infarction.
2. Stroke is a blockage in the arteries to the brain that causes damage or death of brain tissue
3. Risk includes Smoking, High blood pressure, High cholesterol, Diabetes, Obesity

Question 9

What makes the heart beat?

Answer 9

1. Contractions can occur spontaneously because of a specialized group of myocardia (sets rhythm of heart and sits at atrium)
2. SA node regulates automatically, which also sends electrical impulse to walls of the atria (first little hump on normal sinus rhythm)
3. Impulse reaches AV node, which delays it (straight line stopping point on normal sinus rhythm)
4. Bundle branches carry signals from AV node to heart apex (sharp decline on normal sinus rhythm)
5. Signal spreads through ventricle walls, causing contraction (large spike then drop on normal sinus rhythm)

Question 10

How can we read an ECG

Answer 10

1. First small bump: An electrical impulse travels from the sinoatrial node to the walls of the atria, causing them to contract
2. Flat line: the impulse reaches the atrioventricular node, which delays it
3. Decrease: bundle branches carry signals from the atrioventricular node to the heart apex
4. Apex: the signal spreads through the ventricle walls causing them to contract

Question 11

In a normal sinus rhythm

Answer 11

it is evenly spaced on EKG and shows regular beats

Question 12

Bradycardia

Answer 12

complexes normal / even, but rate is <60 bpm

Question 13

Tachycardia

Answer 13

complexes normal / even, but rate is >100 bpm

Question 14

Atrial fibrillation

Answer 14

baseline is irregular, ventricular response is irregular

Question 15

Ventricular fibrillation

Answer 15

rapid, wide irregular ventricular complexes

Question 16

Arteriosclerosis and artherosclerosis

Answer 16

umbrella term for Atherosclerosis and Arteriosclerosis
Has to do with an artery being thicker, harder, and less elastic
ARTERIO- hardening of arterioles
Can cause:
ARTHERO: hardening from plaque in in endothelium
Endothelium protects the vessel wall and prevents clotting
Damage to it can occur from low density lipoprotein, smoking, and increased blood pressure
Forms a fatty streak where platelets release growth factors that increase smooth muscle cells, which multiply and secrete collagen in the tunica media
THIS leads to calcium crystals that would normally be deposited to stiffen arteries and stick where they are

Question 17

what do Arteriosclerosis and artherosclerosis cause

Answer 17

Foam cells exposed, immediate blood clot
Weakens artery walls (aneurysms)
Kidneys think BP is low, activate the R-A-A system, and increase blood volume leading to hypertension

Plaque breaks off → embolisms on the loose
Atherosclerosis is an inflammatory disease through c reactive program, can act as a red flag that it’s happening

sometimes this will crack, creating a blood crack , leading to less blood and downstream cell damage can occur

Question 18

What is the content of blood

Answer 18

White blood cells, red blood cells, and plasma (water and protein), hemoglobin (inside the RBC)

Question 19

What is anemia, what can cause it, and how can it be treated?

Answer 19

Anemia is linked to red blood cell function, causing weakness, fatigue, and heart failure due to a lack of oxygen (red blood cells carry oxygen)

Hemoglobin: red blood cells are essentially bags of hemoglobin
Iron center containing heme pigment which can directly bind to 4 oxygen molecules
Consists of 4 globin (2 alpha and 2 beta polypeptide chains) and four heme groups

Question 20

What causes anemia, how is it treated

Answer 20

Can be caused by:
Destruction of bone marrow where RBCs are produced (less RBCs)
Low iron in diet (less hemoglobin)
Mutation in hemoglobin such as sickle cell disease (abnormal hemoglobin)

Can be treated with: (depends on severity and cause)
Injectable EPO
Can be dangerous in regards to performance enhancing drugs
Iron supplements
Blood transfusion

Question 21

How are oxygen and carbon dioxide transported by the blood?

Answer 21

O2– low affinity means there is more O2 leaving, and increased CO2 uptake

CO2– there is more co2 in the blood makes the blood more acidic, which changes its shape to further lower affinity

Question 22

What mechanism maintains the necessary blood oxygen level?

Answer 22

Erythropoietin (EPO) → kidney receptors detect low levels, signal kidneys to produce more EPO, which causes hematocrit to rise and an increase in RBC production

Question 23

What is hemostasis and what are some of the factors that support it?

Answer 23

Hemostasis: The process that stops bleeding at the site of an injury while maintaining normal blood flow elsewhere in the circulation

Vascular spasm & platelet plug
Step 1: Vascular spasm - smooth muscle contracts, causing vasoconstriction
Step 2: Platelet plug formation - injury to the lining of vessel exposes collagen fibers; platelets adhere
Platelets release chemicals that make nearby platelets sticky; platelet plug forms
Step 3: Coagulation - fibrin forms a mesh that traps red blood cells and platelets, forming the clot