Heart & Cardiovascular system Flashcards
What is systemic circulation?
supplies blood to & drains blood from the body.
What is pulmonary circulation?
transports blood to & from the lungs to receive oxygen.
Explain the lymphatic system, how it produces lymph, and how this returns.
At capillary beds blood is passing through, releasing a lot of plasma from the blood which bathes the cells, at this point it is called the interstitial fluid. Most of this makes its way back into the blood vessels. However, some of it is absorbed by lymphatic vessels, and produces what’s now called lymph - a filtrate of blood.
Network of drainage vessels for returning lymph to blood circulatory system.
Transports lymph via lymph nodes for ‘screening’ - immune response.
General S&F of arteries
Thick muscular wall
Narrow lumen
Carry high-pressure blood away from the heart.
Pulse
Detailed structure of arteries
3 layers called “tunica” (=coat):
Tunica intima
Inner layer
Thinnest as single layer of cells
Tunica media
Thickest layer
Lots of elastic fibres & smooth muscle
Elastic recoil → pulse
Tunica adventitia/externa
Outermost layer
Connective tissue
Anchors blood vessel
Role of capillaries
One cell thick, to shorten diffusion distance which maximises diffusion
General S&F of veins
Thin walled and floppy
Wide lumen
Carry low-pressure blood bac to heart
Valves to prevent backflow
Detailed structure of veins
Tunica intima
Inner layer
Thinnest – single layer of cells
Tunica media
Thinner than in arteries
Lots of elastic fibres & some muscles
Much stretchier than arteries
Tunica adventitia/externa
Outermost, thickest layer
Connective tissue
Anchors blood vessel
Explain the role of valves.
Veins have lower pressure than arteries
Valves needed to prevent backflow
Muscular contraction aid venous return
Negative pressure in thorax with inspiration ‘suck’ blood towards heart.
What is BP? How is it measured?
BP varies between systolic pressure (ventricles contracting) and diastolic pressure (heart relaxed and filling with blood)
Measured at brachial artery using a sphygmomanometer and stethoscope.
What are clinical pulses? How can they be measured?
Caused by elastic recoil of arteries
Can be palpated anywhere an artery can be compressed near the surface of the skin
Eg: Carotid pulse - neck, Radial pulse - felt at wrist in anatomical snuffbox
What are the layers of the pericardium?
Fibrous pericardium (outermost)
Strong fibrous layer
Firmly attached to diaphragm below
Attached in front to sternum
Fuses with outer layers of great vessels that pass into pericardium
Serous pericardium (middle 2 layers)
2 layers
Parietal - lines the fibrous pericardium
Visceral - closely covers heart
There is a small space between these layers called the pericardial cavity
This contains pericardial fluid (lubrication)
Explain role of RA
Receives DEOXYGENATED blood from body via SVC & IVC
Pectinate muscles, muscular ridges (only found in atria – mainly in RA)
Right auricle (remnant of fetal development)
SA & AV nodes
Fossa ovalis
Remnant of foramen ovale (hole) in atrial septum in fetal life
Opening for coronary sinus (coronary sinus drain coronary veins found in muscles of heart wall)
Tricuspid atrioventricular valve leading to right ventricle
Explain role of RV
Receives DEOXYGENATED blood from right atrium via tricuspid AV valve
Trabeculae carneae (only found in ventricles)
Muscular wall thicker than atria
Papillary muscles & chordae tendineae attach to valve leaflets
Prevent backflow of blood into atrium
Pulmonary semilunar valve leading to pulmonary trunk → pulmonary arteries to the lungs
Explain role of LA
Receives OXYGENATED blood from lungs via 4 pulmonary veins
Smooth-walled except for left auricle (pectinate muscles)
Fossa ovalis (more obvious in RA) (use to be a hole in interatrial septa)
Bicuspid (or mitral) atrioventricular valve leading to left ventricle
