Chapter 11 - Cardiovadcular System Flashcards
What are the three types of blood vessels in the body?
Arteries, veins and capillaries
What are the arteries?
A large blood vessels that carry blood AWAY from heart
Their walls are lined with connective tissue, muscle tissue and elastic fibres, with an innermost layer of epithelial cells called endothelium
What do endothelial cells do?
Found in all blood vessels. They secrete factors that affect size of blood vessels, reduce blood clotting, and promote the growth of blood vessels.
They must be strong enough to withstand High pressures of pumping action from heart. Their elastic walls allow them to expand as the heartbeat forces blood into arterial system throughout body
What are arterioles?
Smaller branches of arteries. Thinner than arteries and carry blood to tiniest of blood vessels, the capillaries
What do the capillaries do?
Carry oxygenated blood from arteries and arterioles to the body cells
Where does the nutrients from the blood in the capillaries go?
The capillaries thin walls allow the oxygen and nutrients out of the bloodstream and into the cells. There, nutrients are burned in presence of oxygen (catabolism) to release energy
While the nutrients are burning, what is happening at the same time with the waste products?
Waste products (H2O and CO2) pass out of the cells and into the thin-walled capillaries. The waste-filled blood then flows back to the hear in small venules, which combine to make larger vessels called veins
What are veins?
Thinner walls than arteries. They conduct blood that’s given up most of its oxygen toward the heart from the tissues
Veins compared to arteries
Veins: little elastic tissue and less connective tissue than arteries. Blood pressure in veins is extremely low compared to pressure in arteries.
How does the blood keep moving back toward the heart in the veins?
They have valves that prevent backflow of blood and to keep the blood moving in one direction. Muscular action also helps movement if blood in veins
Oxygen poor blood enters right side of heart and then travels to pulmonary artery. Where do the two branches of the pulmonary artery lead to?
One branch leads to the left lung, the other to the right lung
What do the branches of the pulmonary artery do?
Continue to divide and subdivide within the lungs, forming smaller and smaller vessels (arterioles) and then reaching the lung capillaries.
Pulmonary artery is only artery in body that carries oxygen deficient blood
While passing through lung (pulmonary) capillaries, blood absorbs the oxygen that entered body through inhalation. Where does the newly oxygenated blood go?
It returns immediately to the heart through pulmonary veins.
Pulmonary veins are only veins that carry oxygenated blood
What is pulmonary circulation?
Circulation of blood through vessels from the heart to the lungs and then back to the heart again
Oxygenated blood enters left side of heart from pulmonary veins. What happens next?
Left side of heart pumps blood out of heart through the aorta
What is the single largest artery in the body?
The aorta
Aorta moves up at first (ascending aorta) then arches over doesally and runs downward (descending aorta) right in front of the vertebral column. What does it do then?
Aorta divides into numerous branches called arteries that carry oxygenated blood to all body parts
What are some arterial branches?
Brachial, axillary, splenic, gastric, and renal arteries
What do the carotid arteries do?
Supply blood to the head and the neck
What do the arterial vessels, and what happens afterwards?
They branch further to form smaller arterioles, still carrying oxygenated blood. The arterioles then branch into smaller tissue capillaries, near the body cells.
Where does the oxygen leave the blood and where does it go?
It leaves in the tissue capillaries through the thin walls of the capillaries. This is where food is broken down, in the presence of oxygen, and energy is released (catabolism)
What happens to the blood as oxygen leaves?
CO2 then leaves cells and enters into tissue capillaries. So the blood returning to the heart from tissue capillaries through the venules and veins is oxygen deficient and CO2 filled.
Where does the oxygen poor blood enter the heart from?
The venae cavae
What is systemic circulation?
Pathway of blood from heart to tissue capillaries and back to the heart
Where does the heart lie?
In the thoracic cavity, just behind the breastbone in the mediastinum (between the lungs)
How many chambers does the heart have?
- 2 upper chambers called atria. 2 lower chambers called ventricles
Blood enters venae cavae (2 largest veins). What does the Superior Vena Cava and the Inferior Vena Cava do?
SVC: drains blood from upper portion of body
IVC: carries blood from lower part of body
Where do the venae cavae bring the oxygen-poor blood, and what happens when it’s there?
It goes to the atrium (thin walled in upper right chamber). The right atrium contracts to force blood through the tricuspid valve into the right ventricle (lower right chamber).
What does the tricuspid valve do?
It’s a one way passage for blood to flow. It prevents backflow into the right atrium.
During what does the tricuspid valve stay shut?
When the right ventricle contracts oxygen poor blood through the pulmonary valve, and into the pulmonary artery
What does the pulmonary artery do with oxygen poor blood?
It branches out and carries it to each lung
What happens to the blood once it enters the lung capillaries?
It loses its CO2 into lung tissue and oxygen enters and is brought back to the heart in the pulmonary veins, newly oxygenated blood.
Where does the oxygenated blood enter? What happens then?
Enters the left atrium from the pulmonary veins.
Walls of left atrium contract to force blood though the mitral valve (bicuspid) and into the left ventricle
What does the left ventricle do?
Propels blood through the aortic valve and into the aorta, which branches to carry blood all over body (aortic valve closes to prevent return of aortic blood)
What are the four chambers of the heart separated by?
Separated by partitions called Septa (singular: septum)
Which septa separates what chambers?
Interatrial septum separates the two upper chambers (atria) Interventricular septum (muscular wall) lies between two lower chambers (ventricles)
What are the three layers of the heart?
Endocardium. Myocardium. Pericardium.
What is the endocardium and where does it lie?
A smooth layer of endothelial cells. It lines the interior of the heart and heart valves.
What is the myocardium?
It’s the middle and muscular layer of the heart wall. Thickest layer (myo=muscle)
What is the pericardium and where is it located?
A fibrous and membranous sac and surrounds the heart. Has two layers
What are the two layers of the pericardium?
Visceral pericardium. Parietal pericardium
Where is the visceral pericardium?
It sticks to the heart
Where is the parietal pericardium?
(Parietal means wall). It lines the outer fibrous coat
Where is the pericardial cavity and what does it do?
It’s between the visceral and parietal pericardial layers.
It contains some pericardial fluid to lubricants membranes as the heart beats
What are the two phases of heartbeat?
Diastole (relaxation)
Systole (contraction)
When does diastole occur, and what happens during it?
When ventricle walls relax and blood flows into heart from the venae cavae and pulmonary veins.
Tricuspid valves open in diastole, as blood passes from right and left atria into the ventricles. Pulmonary and aortic valves close during diastole
When does systole occur and what happens during it?
After diastole. As walls of right and left ventricles contract to pump blood into pulmonary artery and the aorta.
Both tricuspid and mitral valves are closed during systole to prevent backflow into atria
Closure of heart valves is associated with sounds “Lubb-dubb” heard in a stethoscope. What valves are closing in each one?
Lubb: closure of tricuspid and mitral valve in beginning of systole. First heart sound (S1)
Dubb: closure of pulmonary and aortic valves at the end of systole. Second heart sound (S2)
What causes a murmur?
Flow of blood through valves can produce an abnormal swishing sound
What is primary responsible for initiating the heartbeat, and where is it located?
Sinoatrial node (SA nodes) or pacemaker. Rests with a small region of specialized muscle tissue in posterior portion of right atrium, where electrics impulse originates
What does the pacemaker do?
The current of electricity generated by the pacemaker chases the walls of the atria to contract and force blood into the ventricles
The wave of electricity passes from pacemaker to another region of the myocardium. Where does it go to?
It goes to atrioventricular node (AV node), within the ineratrial septum.
What does the AV node do?
Sends the excitation wave to a bundle of specialized muscle fibres called ‘atrioventricular bundle’ or ‘bundle of His’.
Within the interverntricular septum, what does the bundle of His do?
They divide into left bundle branch and right bundle branch, which form the conduction multiverse that extend through the ventricle walls and contract on stimulation. Systole then occurs and blood is pumped away from heart.
Short rest then pacemaker starts again.
What is an electrocardiogram (ECG or EKG) used for?
Detecting electrical changes in heart muscle as heart beats
What are the 5 waves or deflections on an EKG tracing?
P, QRS, T
Why is Normal Sinus Rhythm (NSR)?
Heart rhythm, starting in SA node and travelling through the heart.
When do sympathetic nerves happen?
Speed up heart rate during conditions of emotional stress or vigorous exercise
When does parasympathetic nerves happen?
Slow heart rate when no need for extra pumping
What is blood pressure?
The force that blood exerts on the arterial walls
What is blood pressure measured with, and what is it?
Sphygmomanometer. (Things at pharmacies) It’s a rubber bag inside a cloth cuff that’s wrapped around upper arm. Rubber bag is inflated, and the pressure within it increases and is measured on a recording device attached to cuff.
What is systole pressure?
Pressure in artery when left ventricle is contracting to force blood into Aorta and other arteries
What is diastole pressure?
Pressure in artery when ventricles relax and heart fills, receiving blood from venae cavae and pulmonary veins
Blood pressure is expressed as fraction ex. 120/80 mm Hg. Which number represents which pressure type?
Upper number (120) is systolic pressure Lower number (80) is diastolic pressure
What is hypertension (HTN)?
High blood pressure. Blood pressure greater than 140/90mm Hg.
What is arrhythmias?
Abnormal heart rhythms (dysrhythmias)
-problems with conduction or electrical system of heart
What treatment can overcome arrhythmias?
Implantation of an artificial cardiac pacemaker. Keeps heart beating at proper rate
What is fibrillation?
Very rapid, random, inefficient, and irregular contractions of the heart (350+beats per min)
What are the two types of fibrillation?
Atrial fibrillation (AF): electrical impulses move randomly within atria, causing atria to quiver instead of contracting Ventricular fibrillation (VF): electrical impulses mover randomly within the ventricles
What is PVC?
Preventricular contractions
What is tetralogy of Fallot?
Congenital malformation involving four distinct heart defects
- pulmonary artery stenosis
- ventricular septal defect
- shift of aorta to the right
- hypertrophy of the right ventricle
What is congestive heart failure (CHF)?
Heart is unable to pump it’s required amount of blood Pulmonary edema (fluid accumulation in lungs) and swelling or edema in legs, feet and ankles are common signs
What is coronary artery disease (CAD)?
Disease of the arteries surrounding the heart
Usually result of atherosclerosis
What is angina (pectoris)?
Chest pain at rest or intervals (arteries are narrowed)
What is thrombotic occlusion?
Blocking of the coronary artery by a clot
What is ischemia?
Occurs when blood is held back from an area
Can cause a myocardio infarction (MI)
May result from artery disease or thrombotic occlusion of a blood vessel
What is myocardial infarction (MI)?
A heart attack. The area of dead myocardial tissue is known as an infarct.
Caused from ischemia and death (necrosis) of part of myocardium.
What is nitroglycerin?
Used for acute attacks of angina. Given under the tongue (sublingually)
What is pericarditis?
Inflammation of the membrane (pericardium) surrounding the heart
What is rheumatic heart disease?
Heart disease caused by rheumatic fever
What is an aneurysm?
Local widening (dilation) of an arterial wall
What is DVT?
Deep vein thrombosis (blood clot forms in a large vein, usually in lower limb)
What is an angiography?
X-ray imaging of blood vessels after injection of contrast material
What is ECHO?
Echocardiography. (Echoes generated by high-frequency sound waves produce images of the heart y
What is atrial fibrillation on an EKG?
P waves are replaced by irregular and random fluctuations. No effective atrial contractions
What is ventricular tachycardia on an EKG?
Ventricular rate may be as high as 250 beats per min. Rhythm is regular but atria are not contributing to ventricular filling and blood output is poor
What is ventricular fibrillation on an EKG?
Abnormal, irregular waves. Ventricles in fibrillation can’t pump blood effectively. Circulation stops and sudden cardiac death follows if not defibrillated.
What is CABG?
Coronary artery bypass grafting. Arteries and veins are anastomosed to coronary arteries to detour around blockages
What is defibrillation?
Brief discharges of electricity applied across chest to stop ventricular fibrillation
