Cardvascular System Feb 27 - part 1 Flashcards
What are the major organs and structures involved in the cardiovascular system?
Heart, arteries, veins
Each organ plays a critical role in circulation and blood flow.
Where is the heart located?
Mediastinum
Bordered by lungs, diaphragm, spine, sternum, and soft tissues of the neck.
What is the apex of the heart’s orientation?
Points obliquely to the left and anterior
The right ventricle faces towards the sternum.
What is the function of the pericardium?
Contains the heart within a strong and inelastic sac
It has three layers: visceral, parietal, and fibrous.
What are the three layers of the heart wall?
- Epicardium
- Myocardium
- Endocardium
Each layer has distinct functions related to heart structure and function.
What is the function of the myocardium?
Functional muscle of the heart
Responsible for the contraction of the heart.
What prevents backflow of blood into the atria during systole?
Tricuspid Valve
Also known as the right atrioventricular valve.
What are the primary pacemakers of the heart?
- Sinoatrial node (SA node) - 60-100 BPM
- Atrioventricular node (AV node) - 40-60 BPM
- Purkinje fibers - 20-40 BPM
Each pacemaker has a different intrinsic rate of firing.
What is cardiac output (CO)?
CO = SV x HR
Stroke volume (SV) is the amount of blood pumped per beat, and heart rate (HR) is the number of beats per minute.
What is Starling’s Law?
The more the heart fills with blood, the stronger the contraction
It relates to the relationship between preload and stroke volume.
What is the difference between arteries and veins?
- Arteries: High pressure system, thicker walls, carry blood away from the heart
- Veins: Low pressure system, thinner walls, carry blood back to the heart
Veins have valves to prevent backflow.
What is meant by pulse pressure?
The difference between systolic and diastolic pressure
Normally about 40 mmHg.
What is the role of baroreceptors in heart rate regulation?
Measure pressure and stretch on blood vessel walls
They send signals to the CNS to adjust heart rate based on blood pressure.
What are the effects of sympathetic stimulation on heart rate?
Increased HR, increased force of contraction, increased vascular tone
Mediated by hormones like epinephrine and norepinephrine.
What does a murmur indicate?
Abnormal blood flow patterns in the heart
Can suggest valvular issues or other cardiac conditions.
What are the three factors that affect stroke volume?
- Preload
- Contractility
- Afterload
Each factor can positively or negatively influence stroke volume.
What is the function of the endocardium?
Prevents clots and turbulence
It’s a continuous lining of the heart and blood vessels.
What is the cardiac reserve?
The ability of the heart to increase CO due to increased demand
It reflects the heart’s capacity to respond to stress.
What is the primary role of the coronary arteries?
Supply oxygen and nutrients to the myocardium
They are fed during diastole.
What is the cardiac cycle?
The sequence of events in one heartbeat, including systole and diastole
Involves contraction and relaxation of heart chambers.
What causes the ‘LUBB’ and ‘DUBB’ sounds in the heart?
- S1 (LUBB): Closing of AV valves
- S2 (DUBB): Closing of semilunar valves
These sounds are associated with turbulence created during heart contractions.
What is the function of the liver and spleen in blood circulation?
Filtered and cleaned every time it goes through
Filters approximately 1L/min, produces and stores hormones, enzymes, and RBCs.
What is hepatic circulation?
The process through which absorbed nutrients are cleaned through the portal system before entering systemic circulation.
It connects the digestive organs to the liver.
How does fetal circulation differ from adult circulation?
In utero, oxygen is supplied by the placenta via the umbilical cord, bypassing the lungs.
Blood that goes to the lungs becomes deoxygenated.
What is the role of the ductus arteriosus and foramen ovale in fetal circulation?
They allow blood to bypass the lungs.
Ductus arteriosus connects the pulmonary artery to the aorta.
What are the three main functions of the cardiovascular system?
- Transportation
- Protection
- Regulation
This includes the transport of O2, CO2, waste, nutrients, and pH regulation.
What are the two main components of blood?
- Plasma (55%)
- Formed elements (45%)
Formed elements include RBCs, WBCs, and platelets.
What is anemia?
A decrease in hemoglobin or hematocrit.
Hemoglobin has a higher affinity for CO than O2.
What is the lifespan of a red blood cell (RBC)?
120 days.
RBCs are made in red bone marrow and are anucleated.
What are the types of white blood cells (WBCs)?
- Neutrophils
- Basophils
- Eosinophils
- Lymphocytes
- Killer T-Cells
- Helper B-Cells
WBCs are nucleated and protect the body.
What is the primary function of platelets (thrombocytes)?
Responsible for blood clotting and plug formation.
They help maintain hemolytic/hydrostatic balance.
What is interstitial fluid (ISF)?
Fluid in between cells, outside of the circulatory system.
Its composition changes as blood and surrounding cells exchange substances.
What is the process by which lymph enters the lymph vessels?
Filtration through pores in the walls of capillaries.
Lymph travels to lymph nodes before mixing with blood.
What are the three basic mechanisms of hemostasis?
- Vascular spasm
- Platelet plug formation
- Blood clot formation
Clot formation is a positive feedback process.
What is the role of the fibrinolytic system?
It dissolves clots once the vessel wall is repaired.
Plasmin in platelets is involved in this process.
What is the average circulating blood volume for adult males and females?
- Males: 5-7L
- Females: 4-6L
Approximately 71ml/kg is a rough estimate.
What are the two major blood groups?
- ABO
- Rh
ABO is based on glycolipid isoantigens A and B.
What does Rh+ and Rh- signify in blood types?
Rh+ has Rh antigens (universal recipient), Rh- lacks them (universal donor).
Rh antigens are named after the Rhesus monkey.
What happens to heart rate during exercise?
Heart rate increases initially but may drop to a steady state during prolonged exercise.
This is known as cardiac drift in hot climates.
What is stroke volume and how does it change with exercise?
Stroke volume increases from 70ml/beat to 110-130ml/beat.
Elite athletes can increase stroke volume to 200ml/beat.
What happens to blood flow distribution during exercise?
At rest, 15% of blood flow supplies skeletal muscle; during exercise, it increases to 80-85%.
Blood is shunted from major organs.
What are the adaptations of the cardiovascular system to exercise?
- Increased heart mass and volume
- Decreased resting heart rate
- Increased stroke volume at rest
- Increased blood and plasma levels
These adaptations lead to more effective blood redistribution.
What changes occur in blood pressure during exercise?
Systolic blood pressure increases while diastolic remains relatively constant.
A change of 15mmHg in diastolic pressure can indicate coronary heart disease.
How does aging affect blood volume and composition?
The volume and composition of blood remain constant, but red bone marrow decreases, leading to slower recovery from bleeding.
WBC activity also declines with age.
What happens to blood vessel walls with aging?
They become thicker and tougher, increasing the risk of aneurysms and thrombus formation.
Weakened walls can collect calcium salts.
What cardiovascular changes occur in the heart with aging?
- Reduced exercise cardiac output
- Heart muscle loses elasticity
- Heart valves thicken
- Decreased pacemaker cells
- Increased arrhythmias
Aging leads to a higher likelihood of atherosclerosis.
What is syncope and what can cause it?
A loss of consciousness due to prolonged standing still, caused by the absence of skeletal pumping and deep breathing.
This can lead to dizziness and falls.
