Respiratory Cardio-Vascular (RCV) I Flashcards
Describe the heart
12cm long, 9cm wide, weighs between 8-10oz, lies on diaphragm in 2/3 to left of midline in thoracic cavity, apex = anterior and inferior, base = posterior and superior
Describe the 3 different layers of the heart
pericardium - parietal and visceral layers, myocardium - muscular middle layer, endocardium - inner endothelial layer
Describe the pericardium layer of the heart
outermost parietal layer is fibrous - protects the heart and keeps it in position, inner layer of visceral pericardium is a serous layer, pericardial fluid lies between the parietal and visceral layers in the pericardial cavity - reduces friction between the membranes
Describe the myocardium layer of the heart
muscle fibres arranged diagonally as interlacing bundles - involuntary smooth muscle
Describe the endocardium layer of the heart
smooth lining for chambers of the heart, continuous with linings of blood vessels - made of endothelium and connective tissue
Sulci
the grooves on the exterior surface of the heart, they carry the coronary arteries which are the heart’s blood supply
4 chambers of the heart
2 superior atria, 2 inferior ventricles
Atrial septum
divides the atrial chambers into left and right atrium
Interventricular Septum
divides the ventricles into left and right
Describe the flow of blood in the heart from the RA to the RV
RA receives blood from IVC/SVC & coronary sinus (this is blood returning from the coronary supply to the heart tissue), blood passes through the RA to the RV through the tricuspid valve (3 cusps)
Describe the tricuspid valve
made of dense connective tissue covered in endocardium, these connective tissue rings of valves helps prevent them from overstretching
Coronary Sinus
brings blood back to the RA from the coronary arteries supplying the heart tissue
Describe the flow of blood in the heart from the RV to the LV
Blood passes from the RV through the pulmonary valve into the pulmonary trunk where it then divides into 2 arteries - left/right pulmonary arteries, the LA then receives the blood from the pulmonary veins after its passed through the lungs, blood then passes from the LA to the LV through the bicuspid (mitral) valve (2 cusps)
Describe what happens with the blood after it has left the LV
blood passes from the LV into the ascending aorta (AA) through the aortic valve, as blood is pushed from the heart the pressure increases within the aorta driving blood into the coronary circulation to supply the heart tissue, eventually this drains back through the coronary veins into the coronary sinus, the remainder continues through the AA and onto the descending (thoracic/abdominal) aorta, branches come off the aorta to supply the rest of the body
Describe the muscle distribution between the atrium and the ventricles
thicker muscle in the ventricles than atria because the blood has to be pumped further - assisted by the muscular covering of myocardium, RV & LV pump blood at the same time but LV has to push the blood a greater distance
Describe what the valves respond to
respond to pressure changes in the chambers and open to allow this blood flow but close accordingly preventing back flow
Name the 2 atrioventricular valves
tricuspid and bicuspid (mitral)
Describe the role of valves in the blood flow of the heart
when the atrioventricular valves open the cusps point into the ventricles allowing blood flow from atria to ventricle, as blood moves from RV to pulmonary trunk, its upward movement closes the AV valve and opens the pulmonary valve (same from LV into aorta with the aortic valve), as ventricles relax the blood flows back towards the heart filling the cusps of the valves and forcing them to close preventing back flow
Describe the pulmonary circulation that occurs
The RA receives dark red, de-oxygenated blood from IVC & SVC, this blood then travels from RA to RV and up into the pulmonary trunk where it then travels through the left & right pulmonary arteries into the right & left lungs where these arteries then become arterioles & capillaries, it does this for gaseous exchange, once it reaches the capillaries it unloads CO2 (exhaled) and picks up O2 (inhaled) via diffusion across thin membranes of blood capillaries and alveoli, blood then continues through venules which become veins and onto pulmonary vein returning to the RA
Describe the role of the autorhythmic fibres - 3 points
these trigger a heart contraction and cause it to beat, can still trigger contractions without a nervous system, specialised cardiac fibres act as a pacemaker creating an effective pump
Describe the pathway of the contraction of the heart - 5 points
sino-atrial node (found just inferior to the opening of the SVC), stimulation of the SAN reaches the atrioventricular node (AVN) which affects the AV bundle known as the Bundle of His, this therefore activates the ventricular fibres and the inter-ventricular septum, the wave then reaches the Purkinje Fibres sending contractions upwards form the apex of the heart
Describe the cardiac output and under what circumstances it differs and why - 3 points
SA node initiates contraction, set rate of approximately 72 beats per minute, however this differs under different conditions (e.g. exercise/rest/stress) - requires cardiac rate to change, chemicals (e.g. hormones) & O2 levels alter output, Age/Gender/Temperature also effect the cardiac ouput
Describe the cardiovascular centre
its in the medulla oblongata of the brain, receives input from a variety of sensory receptors and directs appropriate output by increasing/decreasing nerve impulses
The Respiratory System consists of … - 6 points
nose, pharynx, larynx, trachea, bronchi, lungs
Respiratory portion of the lungs consist of … - 3 points
respiratory bronchioles, alveolar ducts and alveolar sacs
Describe the nose - description and purpose
mainly cartilaginous with an opening via the naris (nostrils), warms & moistens air by secretions of mucus from goblet cells within the inner lining of the nasal cavity
Describe the role of the mucus in the nose - 3 points
filter the air as it passes through the course hairs of the nasal cavity, adds resonance to the voice, detects olfactory stimulus in sense of smell
Describe the nasal cavity - 4 points
the space within the internal nose, subdivided, cavity consists of hyaline cartilage and is divided by nasal septum, ducts from the sinuses and tear ducts interconnect with the nasal cavity
Describe the nasal conchae - description and role - 4 points
subdivide the nasal conchae (formed by Turbinate bones) into the superior/middle/inferior meatuses forming groove-like passages, these conchae increase surface area, prevent dehydration by trapping water droplets during exhalation
Describe the pharynx - 4 points
lies posterior to nasal & oval cavities, lined with mucus membrane, provides passageway for food and air, divided into nasa/oro/laryngo pharynx
Nasal Pharynx - 1 point
lined with cilia (hair-like projections) to sweep dust particles towards lower pharynx
Oro-pharynx - 2 points
this is from the soft palette to the hyoid bone, lined with stratified squamous epithelium to help protect it from abrasive foods
Stratified squamous epithelium
flattened epithelial cells arranged in layers upon a basal membrane
Laryngo-pharynx - 2 points
same lining as oro-pharynx (stratified squamous epithelium) and opens into oesophagus posteriorly and voice box anteriorly
Describe the larynx
passageway to join pharynx to the trachea, C4-C6, consists of thyroid & cricoid cartilage, epiglottis and vocal folds
Describe how food is prevented from entering the trachea during swallowing
as the pharynx widens to accept food, the epiglottis moves down to form a ‘lid’
Describe and explain the lining of the larynx - 4 points
stratified squamous epithelium, for protection against abrasive foods, ciliated to waft dust particles, goblet cells secreting mucus to moisten air or food
Describe the trachea - size, position - 4 points
12cm long, 2.5cm in diameter, anterior to oesophagus, runs from larynx to T4/T5
Name the 4 layers of the trachea and describe its lining - 3 points
layers include mucosa, submucosa, hyaline cartilage, areolar connective tissue, lined with epithelium for protection, goblet cells secrete mucus, ciliated to help expel any dust particles
Describe the structure of the trachea - 3 points
16-20 incomplete rings made of hyaline cartilage, incomplete posteriorly because in contact with the oesophagus therefore accommodates swallowing, cartilaginous rings prevents the trachea collapsing
Describe the bronchi
trachea splits into right/left main bronchi at T4/T5, right bronchus is more vertical/straighter/wider, internal ridge is known as the carina at this division
Describe the lining of the bronci
lined with mucus membrane which is sensitive and will trigger a cough reflex if needed - minimises the number of particles entering lungs
