Heart and blood vessels Flashcards
What is the function of a cardiovascular system, and is it necessary for life?
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 `
Open system
heart, vessels, and blood BUT vessels spill content out into body
Eg. worms that use simple diffusion to exchange gasses across the cell membrane
closed system
vessels never spill out, but constrict to let gasses escape
Eg. Humans
Why does the human heart have four chambers?
We are big and have fast metabolisms that require more oxygen
Path of deoxygenated blood
Inferior vena cava → Right atrium → tricuspid valve → right ventricle → pulmonary valve → pulmonary artery → Lungs
Path of oxygenated blood
Lungs → pulmonary vein → left atrium → mitral valve → left ventricle → aortic valve → aorta
What is cardiovascular disease (CVD)?
Group of disorders of the heart and blood vessels referred to as heart disease and stroke
What causes heart attacks and strokes? What are some of the risk factors for CVD?
- 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.
- Stroke is a blockage in the arteries to the brain that causes damage or death of brain tissue
- Risk includes Smoking, High blood pressure, High cholesterol, Diabetes, Obesity
What makes the heart beat?
- Contractions can occur spontaneously because of a specialized group of myocardia (sets rhythm of heart and sits at atrium)
- SA node regulates automatically, which also sends electrical impulse to walls of the atria (first little hump on normal sinus rhythm)
- Impulse reaches AV node, which delays it (straight line stopping point on normal sinus rhythm)
- Bundle branches carry signals from AV node to heart apex (sharp decline on normal sinus rhythm)
- Signal spreads through ventricle walls, causing contraction (large spike then drop on normal sinus rhythm)
How can we read an ECG
- First small bump: An electrical impulse travels from the sinoatrial node to the walls of the atria, causing them to contract
- Flat line: the impulse reaches the atrioventricular node, which delays it
- Decrease: bundle branches carry signals from the atrioventricular node to the heart apex
- Apex: the signal spreads through the ventricle walls causing them to contract
In a normal sinus rhythm
it is evenly spaced on EKG and shows regular beats
Bradycardia
complexes normal / even, but rate is <60 bpm
Tachycardia
complexes normal / even, but rate is >100 bpm
Atrial fibrillation
baseline is irregular, ventricular response is irregular
Ventricular fibrillation
rapid, wide irregular ventricular complexes
Arteriosclerosis and artherosclerosis
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
what do Arteriosclerosis and artherosclerosis cause
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
What is the content of blood
White blood cells, red blood cells, and plasma (water and protein), hemoglobin (inside the RBC)
What is anemia, what can cause it, and how can it be treated?
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
What causes anemia, how is it treated
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
How are oxygen and carbon dioxide transported by the blood?
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
What mechanism maintains the necessary blood oxygen level?
Erythropoietin (EPO) → kidney receptors detect low levels, signal kidneys to produce more EPO, which causes hematocrit to rise and an increase in RBC production
What is hemostasis and what are some of the factors that support it?
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
