CVR session 2B- The pleura and lungs Flashcards
intercostal spaces-
external intercostal muscle? direction? purpose? features?
External intercostal muscle fibres are orientated antero-inferiorly, contraction of these pulls ribs superiorly (in active inspiration), closer to the sternum the msucle becomes membranous and forms external intercostal membrane.
Internal intercostal muscle- direction? purpose?
Internal intercostal muscle fibres run posterior-inferior direction (perpendicular to external, contraction pulls robs inferiorly and are active in forced expiration
innermost intercostal muscle- direction?
same orientation as internal intercostal muscles (posterior-inferior direction)
Intercostal neurovascular bundle-
neurovascular bundle contains- vein, artery and nerve,
runs superior to the intercostal space between each layer of intercostal muscle, supplies intercostal muscle, skin and parietal pleura
travels in a costal groove on the deep surface of the rib (chest drains are placed in lower part of intercostal space to avoid the bundle)
anterior arteries and veins that supply intercostal muscle? posterior arteries and veins that supply intercostal muscle?
anterior intercostal arteries are brances of the internal thoracic artery (branch of subclavian artery) and supply anterior parts, anterior intercostal veins drain into thoracic artery
posterior intercostal arteries are branches of the descending aorta , posterior intercostal veins drain into azygous system of veins
nerves present in vascular bundles?
intercostal nerves are somatic and contain motor and sensory fibres. They innervate intercostal muscle, skin of chest and parietal pleura. can also carry sympatheic fibres
pleura of the lungs- layers? space?
parietal pleura (visible) lines inside of thorax, visceral pleura (not visible) lines surface of lungs and extends down into the fissures, pleurae are continuos with eachother, pleural cavity inbetween them with pleural fluid
names of the different pleura? what is costomediastinal recess? what is costodiaphragmatic recess?
cervical pleura- apex of lung
costal pleura- adjacent to ribs
mediastinal pleura- adjacent to heart and mediastinum
diaphragmatic pleura- adjacent to diaphragm
costodiaphragmatic recess is where costal pleura becomes continuous with diaphragmatic pleura.
costomediastinal recess lies in junction between costal and mediastinal pleura. These spaces allow lungs to expand during deep inspiration.
innervation of pleura: parietal vs visceral
parietal pleura- intercostal nerves that innervate skin, somatic sensory fibres in these nerves carry info to consciousness
visceral pleura- autonomic sensory nerves, do not reach consciousness
Lobes of the lung- number and name of lobes? fissures- different types and specific location?
- right lung has 3 lobes: superior, middle, inferior
- left lung has 2 lobes: superior and inferior (anterior extension of superior sits over heart- lingula
oblique fissures seperate each lobe (horizontal fissure between middle lobe and superior lobe in right lung), oblique - extend from 4th rib posteriorly to 6th costal cartilage anteriorly
horizontal- extend anteriorly from 4th costal cartilage and intersects oblique fissure
surfaces of the lung?
costal surface- adjacent to rib
mediastinal surface - adjacent to heart and mediastinum
diaphragmatic surface - inferior surface of lung
indenation from adjacent structures e.g. ribs, ventricles etc.
space between inferior border of lungs and parietal pleura?
costodiaphragmatic recess
position of borders of lungs vs parietal pleura
apex of lung- superior to medial end of clavicle
inferior border of lungs-
6th rib midclavicular line
8th rib midaxillary line
10th rib just lateral to vertebral column
parietal pleura-
8th rib mid-clavicular line
10th rib midaxillary line
12th rib just lateral to vertebral column
hilum of the lung- what is it? differnece in left and right lung?
region on mediastinal surface where pulmonary artery, pulmonary vein and main bronchus enter and exit lung.
-Hilum of right lung- pulmonary artery is anterior to main bronchus
-Hilum of left lung- pulmonary artery is superior to main bronchus
whre does trachea bifurcate? what is the ridge of cartilage present there called?
trachea bifurcates at sternal angle and is internall marked by a ridge of cartilage called carina
differnce in left and right bronchus?
right main broncus is shorter, wider and dscends more vertically than left (foreign body more likely to enter right lung)
Bronchial tree:
main bronchus divides into lobar bronchi, 2 on left side, 3 on right side, lobar brochi then divide to segmental bronchi, 10 in right , 8/9 in left
what is a bronchopulmonary segment?
each segmental bronchi supplies a bronchopulmonary segment, each segment supplied by own bronchi and blood vessel so 1 can be removed without affecting others
whats present in trachea, brionchi and bronchioles walls?
trachea and bronchi- smooth muscle and cartilage
bronchioles- only smooth muscle
bronchial arteries and veins- where from? where drain to?
- bronchial arteries from descending aorta supply lung tissue with oxygenated blood.
- bronchial veins return blood to the azygos system of veins
role of parasympathetic and sympathetic in lungs?
autonomic nerves innervate the lungs:
- parasympathetic fibres stimulate constriction of bronchial smooth muscle and secretion from glands in bronchial tree
- sympathetic fibres stimulate relaxation of bronchial smooth muscle and inhibit gland secretion
visceral afferents role in lungs?
visceral afferents (sensory fibres) acompoany autonomic nerves and relay sensory information from lungs and visceral pleura to CNS - not reach consciousness.
lymph drainage in lungs- where to?
venous system via thoracic duct or right lymphatic duct
Inspiration and expiration mechanics?
diaphragm is attached to xiphoid process, costal margin and lumar vertebrae
Central part of diaphragm is fibrous (central tendon)
When diaphragm contracts during inspiration muscle fibres of right and left domes pulled towards their peripheral attachments and the domes flatten. Increase in intrathoracic volume
Diaphragm relaxes and returns to it’s domed shape. This decreases intrathoracic volume and exepels air
