Cardio/Resp Flashcards
How does contraction of pectoralis major assist in breathing?
The two pectoralis muscles form part of a ring of muscles which encircle the thoracic cage; the other muscles forming the ring are the scapula muscles. When the ring contracts the thoracic pressure rises to assist exhalation. This only occurs in disease and during exercise; normal exhalation is a passive process
Which bony structures lie subcutaneously in the anterior chest wall?
The clavicles and sternum (made up of the manubrium, body and xiphi-sternum). The ribs are deep to muscles so are not subcutaneous.
What are the articulations of the clavicle?
At the medial end to the manubrium of the sternum; the sternoclavicular joint and at the lateral end to the acromion of the scapula; the acromioclavicular joint.
What forms the anterior axillary fold?
The lower edge of the pectoralis major muscle.
The lower edge of the pectoralis major muscle.
The axilla.
The majority of breast tissue is in the upper outer quadrant of the breast. Where does lymph from this part of the breast drain?
To the axillary lymph nodes.
Which costal cartilage connects to the sternum at the sternal angle (angle of Louis)?
The second costal cartilage.
Which nerves carry sensation from the parietal and visceral pleura?
The parietal pleura lines the inside of the thoracic wall and is supplied by the same nerves as the tissue of the thoracic wall; the spinal nerves, thoracic 1 to thoracic 12. The visceral pleura covers the surface of the lung and is supplied by the same nerves as the lung; the vagus and sympathetic nerves.
What is a bronchopulmonary segment?
A bronchopulmonary segment has a feeding artery and bronchus which run together through the centre of the segment and repeatedly branch to reach all parts of the segment. The veins which drain the segment run on the surface of the segment rather than through the centre. The ten segments on each side are separated by layers of connective tissue and the fissures. Each segment is anatomically and functionally separate and this influences how diseases may spread through the lungs.
What structures pass through the hilum of the lung?
Main bronchus, pulmonary artery, two pulmonary veins, bronchial artery, lymphatic vessels, branches of the vagus and sympathetic nerves.
How does contraction of the diaphragm assist in returning blood to the heart?
Contraction of the diaphragm decreases intra-thoracic pressure and increases intra-abdominal pressure. The net effect is for blood to flow from the abdomen into the chest.
What is the sensory and motor nerve supply to the diaphragm?
Sensory and motor supply are both from the phrenic nerve which arises from the spinal cord at cervical 3, 4 and 5 segments.
What is the surface markings of the lowest extent of the lungs?
At the midclavicular line to lowest part of the lung lies at the tip of the 6th rib, at the mid-axillary line the 8th rib and posteriorly the 10th rib.
What is intercostal recession?
When a patient is having difficulty taking a breath in and is having to create very negative pressures in the thorax the intercostal muscles get ‘sucked in’.
What is the developmental significance of the ligamentum arteriosum?
It is the remnant of a shunt between the pulmonary artery and the aorta. The shunt carries all the blood from the pulmonary artery into the aorta before the lungs have developed and most of the blood after the lungs have developed. At birth is closes so that all right ventricular blood passes to the lungs.
What are the main branches of the following arteries and what organs/tissues do these vessels supply:
(a) Left common carotid artery
(b) Left subclavian artery
a) Internal and external carotid arteries
External; Left side of the face and head
Internal; most of the cerebral hemispheres
(b) Vertebral, thyro-cervical, axillary
Vertebral; cerebellum, brain stem, occipital lobe and the interior temporal lobe
Thyro-cervical; Thyroid gland and neck
Axillary; upper limb
What are the nerve roots of the phrenic nerve? Why is this clinically important?
Cervical 3, 4 and 5. Painful diseases affecting the diaphragm are felt by the patient in the side of the neck and onto the shoulder tip which is the dermatome supplied by the cervical 3, 4, 5 nerve roots.
What structures are supplied by the vagus nerve?
Pharynx, larynx, heart lungs, fore gut and mid gut.
What are the eight vessels which connect the heart to other structures?
Aorta, pulmonary artery, four pulmonary veins, superior vena cava and inferior vena cava.
What is the surface marking for the apex of the heart?
5th intercostal space, midclavicular line
How may the fibrous pericardium contribute to a reduction in ventricular filling?
Fibrous tissue is resistant to stretching, and so restricts the maximum end diastolic volume. Diseases which ‘take up volume’ in the pericardial sac (eg. fluid, muscle hypertrophy etc.) will reduce diastolic filling and therefore reduce stroke volume. Cardiac output can then only increase by increasing the heart rate. Diseases which progress very slowly (over years rather than days) can stretch the pericardium.
Describe the anatomy of the tricuspid and mitral valves. What happens if they are incompetent?
Both of these valves have a similar structure with the tricuspid having three cusps and the mitral two cusps. The cusps are made of fibrous tissue covered with endothelium and are very flexible. They cusps are attached to a ring of fibrous tissue which forms the orifice between the atrium and ventricle, the myocardium is also attached to this fibrous ring. The free edge of the cusp has multiple tendinous cords attached, the cordi tendini; for each cusp these cords attach to a cylinder of myocardium, the papillary muscle, which contracts during systole to keep the cordi tendini taught.
