Cardiorespiratory System - VOID Flashcards
Label the anterior views of the ribs and sternum.
What are the different joints in the thoracic cage?
Costochondral joints: where the ribs articulate with the costal cartilages.
Sternocostal joints: where the costal cartilages of ribs 1-7 articulate with the sternum. These are the ‘true’ ribs. Ribs 8-10 join (and also with rib 7) to form the ‘costal margin’.
Costovertebral joints: where the ribs articulate anteriorly with the thoracic vertebrae.
What are typical ribs?
Ribs that look similar and share anatomical features ie ribs 3-9. They have a head, neck, tubercle and body (shaft).
Atypical ribs are atypical for various reasons ie ribs 1,2,11 are much shorter than typical ribs.
Label the anatomy of the breast.
- Intercostal muscle.
2. Pectoral muscles.
3. Lobule. - Nipple.
- Areola.
- Ducts.
- Fat.
8. Skin.
Describe the neurovascular supply of the breast.
- Internal thoracic artery (which arises from the subclavian artery).
- Axillary artery.
- Intercostal nerves supply somatic nerves and sympathetic fibres. Somatic sensory fibres innervate the skin of the breast. Sympathetic fibres innervate smooth muscle in the blood vessel walls and nipple.
Describe the lymphatic drainage of the breast.
Most drains to lymph nodes in the axilla, which contains 5 groups of lymph nodes: central, pectoral, numeral, sub scapular and apical.
They drain the breast, upper limb, chest wall, scapular region and the abdominal wall.
The apical nodes (in the apex of the axilla) receive and drain lymph from all other lymph nodes in the axilla.
What are the layers of the thoracic wall?
*External intercostal is most superficial and fibres lie antero-inferiorly. When they contract they pulls the ribs superiorly, so are most active in inspiration.
In the anterior part of the intercostal space, the muscle becomes membranous and forms the external intercostal membrane.
*Internal intercostal lies deep to the external intercostal. Fibres run perpendicular to the external intercostal, in a posterior-inferior direction. Pulls ribs inferiority so is most active in expiration.
It becomes membranous in the posterior part of the intercostal space and forms the internal intercostal membrane.
*Innermost intercostal lies deep to internal intercostal. Fibres lie in the same direction as those of internal intercostal.
The endothoracic fascia lies deep to the innermost intercostal and superficial to the parietal pleura, which surrounds the lung.
These allow inspiration and expiration.
The intercostal spaces also contain a neurovascular bundle, comprising an intercostal nerve, artery and vein. These supply the intercostal muscles.
Describe the pectoralis major.
The most superficial muscle of the anterior chest wall. It attaches to the humerus, clavicle and the upper six ribs.
It adducts the humerus.
Describe the pectoralis minor.
The smaller muscle, lying deep to the pectoralis major. Attaches to the scapula and ribs 3-5.
With the serratus anterior, they protract the scapula.
Describe the serratus anterior.
The muscle superficial around the lateral aspect of the thoracic cage. Attaches to the scapula and upper eight ribs.
With the pectoralis minor, they protract the scapula.
What is the function of the upper limb muscles?
The pectoralis major, pectoralis minor and serratus anterior.
They move the upper limb.
They also act as accessory muscles of breathing. They can move if the humerus and scapula are fixed. Use of these while breathing is a sign of respiratory distress.
Describe the intercostal neurovascular bundles.
Each intercostal space has a neurovascular bundle that supplies it. It lies along the inferior border of the rib superior to the intercostal space, in a shallow costal groove on the deep surface of the rib.
The anterior and posterior intercostal spaces are supplied by the anterior and posterior intercostal arteries, respectively.
The anterior intercostal arteries are branches of the internal thoracic artery (which is a branch of the subclavian artery).
The posterior intercostal arteries are branches from the descending aorta in the posterior thorax.
Anterior intercostal veins drain into the internal thoracic vein.
Posterior intercostal veins drain into the azygos system of veins.
Intercostal nerves are somatic.
They innervate intercostal muscles, skin of chest wall, and parietal pleura. Intercostal nerves also carry sympathetic fibres.
What are the pleurae?
The two layers of membranes that cover the lungs and the structures passing into and out of the lungs. They are separated by a thin pleural cavity (filled with pleural fluid as produced by pleural cells).
Pleural fluid creates surface tension between the pleura on it’s either sides, keeping the thoracic wall together. This means the lung changes volume when the thoracic cavity does during inspiration.
*The parietal pleura lines the inside of the thorax. It is innervate by somatic sensory fibres in intercostal nerves that innervate the overlying skin to the chest wall. It has 4 parts:
Cervical pleura covers apex of lung.
Costal pleura lies adjacent to ribs.
Mediastinal pleura lies adjacent to heart.
Diaphragmatic pleura lies adjacent to diaphragm.
- Visceral pleura cover surface of lungs. Innervated by autonomic sensory nerves (visceral affronts, from which sensation is not normally registered consciously).
What are the costodiaphragmatic and costomediastinal recesses?
Costodiaphragmatic recess: A gutter around the periphery of the diaphragm, where the costal pleura becomes continuous with the diaphragmatic pleura.
Costomediastinal: lies at junction of costal and mediastinal pleura. The lungs expand into these spaces during deep inspiration.
Draw the anatomy of the lungs.
What are the words used to describe areas of the lungs?
Costal surface - adjacent to ribs.
Mediastinal surface - adjacent to the heart.
Diaphragmatic surface - interior surface of the lung.
Anterior border - shape and tapered.
Posterior border - thick and rounded.
Inferior border - sharp and tapered.
What is the root and hilum of the lung?
The root of the lung lies between heart and lung, comprising pulmonary artery and vein and the main bronchus.
The hilum is the region on the mediastinal surface where the root is.
At the hilum of the right lung, the main bronchus lies anterior to the pulmonary artery.
At the hilum of the left lung, the main bronchus lies inferior to the pulmonary artery.
At both hila, the pulmonary veins are the most anterior and inferior vessels.
How does the bronchial tree split?
- Trachea divides left and right at the level of the sternal angle. Contains cartilage and smooth muscle.
- Right main bronchus is shorter, wider and descends more vertically than the left. A foreign body is more likely to enter the right main bronchus.
- Main bronchus divides into lobar bronchi (three in right, two left, one for each lobe).
- Lobar bronchi give rise to segmental bronchi. There are 10 segmental bronchi in each lung. Each supplies an independent region of the lung, called a bronchopulmonary segment.
- Segmental bronchi continue to divide into bronchioles (they become smaller with each division). Bronchioles are made of smooth muscle.
- The alveoli are where gas exchange takes place in the lung.
All muscle is under autonomic control.
Describe the blood and lymph supply of the lungs.
Pulmonary arteries carry deoxygenated blood to the lungs. Bronchial arteries from the descending aorta supply the lungs.
Pulmonary veins return deoxygenated blood to the heart from the lungs.
Bronchial veins return blood to the azygos system of veins.
Lymph is drained via the thoracic duct or right lymphatic duct.
Describe nervous supply to the lungs.
Controlled by autonomic nerves:
* Parasympathetic fibres stimulate:
Bronchostriction
Secretion from glands of bronchial tre.
- Sympathetic fibres:
Bronchodilation.
Inhibit secretion.
Somatic sensory fibres innervate the parietal pleura.
Visceral afferents to relay unconscious sensory information from the lungs and visceral pleura to CNS.
Describe the surface anatomy of the lobes and fissures
Oblique fissure of both L and R lungs extends from 4th posteriorly to 6th costal cartilage anteriorly. The fissure runs deep to the 5th rib.
Horizontal fissure of the R lung extends anteriorly from 4th costal cartilage and intersects the oblique fissure.
What are the functions diaphragm, and how does it contract?
Thin, domed sheet of skeletal muscle.
Integral to mechanics of breathing.
Separates thoracic and abdominal cavities.
During inspiration, the diaphragm contracts, pulling the ends of the muscle fibres towards their peripheral attachments, so the domes flatten. This increases volume of the thoracic cage so the lungs expand.
During expiration, the diaphragm relaxes and domes superiorly. Decreases volume and drives air from lungs.
How is the diaphragm attached and innervated?
To the xiphoid process, costal margin (and to tips of 11th and 12th ribs) and the lumbar vertebrae.
The central part is called the central tendon (it is not muscular).
The right and left phrenic nerves innervate the right and left side of the diaphragm, respectively. They are somatic, formed from C3 and C4 and C5 spinal nerves. Contain motor and sensory fibres.
Describe inspiration
- The diaphragm and external intercostal muscles contract, increasing intrathoracic volume. (External intercostals pull ribs superiorly and laterally, so ribs pull sternum superiorly and anteriorly, increasing lateral dimensions of thoracic cavity).
- Due to surface tension, the lungs expand with the thoracic wall (increase in volume).
- Pressure in lungs decreases below atmospheric pressure send air is drawn into lungs.
Describe expiration.
- Diaphragm and intercostal muscles relax, internal intercostal muscles contract, decreasing intrathoracic volume.
- Lungs recoil (decrease in vol).
- Pressure in lungs increases above atm, so air is expelled.
How to the muscles involved in breathing change?
- Normally, quiet breathing, inspiration is active, expiration is passive. Inspiration mainly driven by movement of diaphragm.
- In vigorous breathing (exercise) the intercostal muscles become important. Active expiration uses internal intercostal muscles.
- in very vigorous breathing, accessory muscles, like pectorals, contribute to movement of ribs and aid ventilation.
What is the mediastinum?
The part of the thoracic cavity that lies between the lungs. It contains things like the heart, oespohagus, trachea etc. There is the inferior and superior mediastinum, separated at the sternal angle anteriorly to the T4/T5 junction posteriorly:
What is the inferior mediastinum?
The inferior mediastinum is divided into anterior, middle and posterior compartments:
*Anterior mediastinum lies between the posterior aspect of the sternum and the anterior aspect of the pericardial sac. It is a narrow space, and contains the thymus gland in children and its remnant in adults.
* middle contains the heart inside the pericardial sac, the pulmonary trunk and the ascending aorta.
* Posterior mediastinum lies between posterior aspect of pericardial sac and the vertebrae.
What is the superior mediastinum?
The main contents of the superior mediastinum are the:
● arch of the aorta and its three branches
● superior vena cava and its tributaries - the left and right brachiocephalic veins
● trachea
● oesophagus
● phrenic nerves (left and right) and vagus nerves (left and right)
● thoracic duct
● thymus gland
Describe the aorta and it’s branches
Ascending aorta is the short, first part, which gives rise to the coronary artery which supply the myocardium.
The arch of the aorta curves posteriorly, and lies in the superior mediastinum. This arch gives rise to three major branches that support the upper body:
● First, the brachiocephalic trunk. It bifurcates into the right common carotid artery (which supplies the right side of the head and neck, including the brain) and the right subclavian artery which supplies the right upper limb.
● Second, the left common carotid artery, which supplies the left side of the
head, neck, and brain.
● Third, the left subclavian artery, which supplies the left upper limb.
The descending (thoracic) aorta descends through the posterior mediastinum and into the abdomen posterior to the diaphragm.
What are the aortic bodies?
In the arch of the aorta, chemoreceptor cells constantly monitor arterial oxgyen and carbon dioxide. The CNS receives this information via the vagus nerve and results in reflex responses that regulate ventilation.
What is the ligamentum arteriosum?
The ligamentum arteriosum is a fibrous, cord-like connection between the pulmonary trunk and the arch of the aorta. It is the remnant of the ductus
arteriosus, a foetal circulatory shunt. In the foetus, gas exchange occurs at the placenta, not in the lungs. The ductus arteriosus diverts most of the blood entering the pulmonary trunk directly to the aortic arch (only a small amount of blood
circulates through the foetal lungs; enough for them to develop). When a baby starts to use their lungs at birth, the ductus arteriosus closes, and blood in the pulmonary trunk enters the lungs.
What is the vena cava?
The two large veins that carry deoxygenated blood from the body to the heart.
The superior vena cava (it and all all its tributaries also lie in superior mediastinum) returns blood from the head, neck and upper limbs.
● The SVC is formed by the union of the left and right brachiocephalic veins (brachium = arm; cephalic = head).
● The union of the internal jugular vein (which drains the head and neck) and the subclavian vein (which drains the upper limb) forms each brachiocephalic vein.
The inferior vena cava returns blood from all regions inferior to the diaphragm.
What is the general structure of the trachea?
It is semi rigid due to C chaped rings of cartilage.
● It extends from the larynx in the midline of the neck into the superior mediastinum and is palpable just superior to the suprasternal notch.
● It terminates at the level of the sternal angle (and junction between the T4 and T5 vertebrae) by bifurcating into the left and right main bronchi.
What are the phrenic nerves?
Left and right phrenic nerves, formed by fibres from C3, C4 and C5 spinal nerves. They innervate the diaphragm, and are somatic nerves. They enter the thorax through the superior thoracic aperture, coursing over the pericardium and piercing the diaphragm.
Describe the vagus nerves.
L and R vagus nerves arise from the brainstem, containing somatic sensory, somatic motor and parasympathetic fibres. They innervate the structures of the thorax, abdomen, head and neck.
● They descend through the neck alongside the internal carotid artery and internal jugular vein and enter the thorax via the superior thoracic aperture.
● They each give rise to a recurrent laryngeal nerve (RLN), which ascend back up into the neck to innervate the muscles of the larynx.
● The left recurrent laryngeal nerve loops under the arch of the aorta before ascending back up the left side of the neck (alongside the trachea) to the larynx.
● The right recurrent laryngeal nerve descends anterior to the right subclavian artery and then loops under the inferior border of the artery before ascending back up the right side of the neck (between the trachea and oesophagus) to the
larynx.
● The vagus nerves descend in the thorax posterior to the root of the lung.
● They contribute parasympathetic fibres to the heart, lungs, and oesophagus.
● They traverse the diaphragm and convey parasympathetic fibres to most of the abdominal viscera.
What is the thoracic duct?
A major channel for lymphatic drainage for most regions of the body. It ascends through the posterior mediastinum and into the superior mediastinum, where it empties into the venous system at the union of the left internal jugular vein and left subclavian vein.
What are the coronary arteries?
L and R coronary arteries arise from ascending aorta and give rise to several named branches, which supply regions of the heart.
Cardiac veins return blood to the coronary sinus, which enters the right atrium.
Describe the right coronary artery and it’s branches.
Supplies parts of conducting system of the heart, RA, RV, part of LV, part of interventricular septum.
Main branches:
* Branches to SAN and AVN supply these.
* Right marginal artery supplies inferior border of heart.
* Posterior interventricular artery (PIV) is the continuation of the right coronary artery on the diaphragmatic surface of the heart. It runs in the posterior interventricular sulcus and supplies both ventricles.
Describe the left coronary artery and it’s branches.
Supplies parts of conducting system of heart, LA, most of LV, part of RV and part of interventricular system.
The LCA runs a short course before it divides into two large terminal branches. This short segment is the left main stem.
The two terminal branches are the anterior interventricular artery (or left anterior descending, LAD) and the circumflex artery (Cx).
The branches are as follows:
* LAD runs in the anterior interventricular sulcus towards the apex. Supplies both ventricles.
* One or two diagonal branches arise from the LAD.
* Circumflex artery runs around the heart onto the diaphragmatic surface, supplying LA, part of RV and part of LV.
* Left marginal artery arises from the circumflex and supplies LV.
Draw the anterior view of coronary circulation
Draw the posterior view of coronary circulation
How do the atrioventricular valves work?
The valve cusps (which project into the ventricle) close passively when pressure rises.
The papillary muscles and chordae tendineae don’t close the valves, but allow the closed valves to resist to the pressure generated, stopping them from being forced open.
When ventricle muscles contract, papillary muscle contract, tensing the cords and pulling on the valve cusps to prevent them from entering the atria.
What are the sympathetic trunks?
Groups of nerves that innervate parts of the upper body.
CNS The two trunks lie on the posterior thoracic wall, either side of the vertebral column and posterior to the parietal pleura. They are thin, longitudinal fibres interspersed with ganglia (known as paravertebral ganglia).
The cell bodies of preganglionic sympathetic neurones lie in the thoracic and upper lumbar spinal cord segments (T1 -L2/3). They exit the spinal cord in spinal nerves T1-L2/3 from it’s ventral aspect and enter spinal nerves T1-L/3 along with somatic motor nerves, whose cell bodies lie in the grey ventral horn.
To summarise:
* Preganglionic sympathetic fibres exit the spinal cord in spinal nerves T1-L2/3.
* Almost immediately, they separate from the spinal nerves and enter the sympathetic trunk via a short connecting branch.
* Once in The sympathetic trunk, the preganglionic axon does one of the following:
1. Synapses in the ganglion at its level of entry.
2. Ascends or descend in the trunk before synapsing in a ganglion.
3. Travels through a ganglion and the trunk without synapsing.
In 1 and 2, the postganglionic axons leaving the ganglia:
* Enter spinal nerves via a communicating branch (grey ramus communicans). Through this, sympathetic fibres enter all 31 pairs of spinal nerves.
* form visceral nerves that convey sympathetic fibres to the head.
* Form visceral nerves that convey sympathetic fibres to the thoracic viscera (cardiopulmonary splanchnic nerves).
What are the triangles of the neck?
There are 2 - the anterior and posterior triangles, separated by the sternocleidomastoid muscle.
Describe the suprathyroid muscles.
Four paired muscles (mylohyoid, geniohyoid, stylohyoid, digastric).
They lie superior to the hyoid bone and form the floor of the mouth.
During contraction, they raise the hyoid bone and larynx during speech and swallowing.
What is the thyroid gland?
It produces hormones which play an important role in the regulation of metabolic processes. The pituitary gland regulates hormone secretion from the thyroid gland.
It is composed of right and left lobes that lie just lateral to the lower larynx and upper trachea. Each lobe lies deep to the sternothyroid muscle.
The two lobes are joined by the isthmus, which lies anterior to the trachea.
Blood supply:
* Left and right superior thyroid arteries. Branches of the external carotid artery.
* The left and right inferior thyroid arteries - branches of the thyrocervical trunks (which are branches of the subclavian artery).
* Superior, middle and inferior thyroid veins drain the gland,
Some people have an additional thyroid ima artery.
Show structure of the pharynx
Describe the structure of the laryngeal skeleton.
Nine cartilages. Three paired (much smaller), three unpaired. Membranes and very small joints connect the cartilages.
Three unpaired:
- Thyroid. The thyroid cartilage is composed of two flat cartilages (laminae) that meet in the anterior midline to form the laryngeal prominence (adam’s apple).
Posteriorly, the laminate form extensions that project superiorly and inferiorly (superior and inferior horns).
The superior horns attach to the hyoid bone.
The inferior forms articulate with the cricoid cartilage below. - Cricoid. The ciricothyroid membrane connects the inferior border of the thyroid and superior border of the cricoid.
- Epiglottis. The epiglottis is attached to the superior aspect of the thyroid cartilage, where two thyroid laminae meet.
Three paired:
* Arytenoids. Sit on upper surface of the cricoid cartilage. They articulate with the cricoid cartilage at small joints. Arytenoids are vital for phonation as the vocal cords attach to them. Movement of the Arytenoids moves the vocal cords.
* Cuneiforms
* Corniculate.
What are the surface markings on the neck?
