Cardio Respiratory 2 Flashcards
Where is the mediastinum?
It extends from superior thoracic aperture superiorly to diaphragm inferiorly (up down)
Sternum anteriorly to thoracic vertebrae posteriorly (front back)
What is in the mediastinum?
All thoracic viscera apart from lungs…
Heart and pericardium
Great vessels with heart
Veins that drain chest wall
Trachea and main bronchi
Oesophagus
Nerves
Lymphatic
The thymus gland
How is the mediastinum split?
Superior and inferior at the point of the sternal angle anteriorly to T4/5 junction posteriorly
How is the inferior mediastinum split?
Anterior, middle, posterior
What’s in the anterior mediastinum?
Between sternum and pericardial sac…
Thymus gland
/remnant of it in adults
What’s in the middle mediastinum?
Heart and pericardial sac
Pulmonary trunk
Ascending aorta
What’s in the posterior mediastinum?
Between posterior pericardial sac and vertebrae
Descending aorta
Main contents of superior mediastinum?
Arch of aorta and 3 branches
Superior vena cava + tributaries + l/r brachiocephalic veins
Trachea
Oesophagus
Phrenic and vagus nerves l/r
Thoracic duct
Thymus gland
3 parts of the aorta?
Ascending aorta (short first part)
Arch of aorta (in superior mediastinum, curves posteriorly)
Descending(thoracic) aorta - descends through posterior mediastinum
What does ascending aorta give rise to?
Coronary arteries that supply myocardium
What does the arch of the aorta give rise to?
Brachiocephilac trunk - bifurcates to right common carotid artery and right subclavian artery
Left common carotid artery
Left subclavian artery
Right common carotid artery?
From brachiocephalic trunk
Supplies right side of head and neck Inc brain
Right subclavian artery?
from braciocephalic artery
Supplies right upper limb
Left common carotid artery?
From arch of aorta
Supplies left side of head, neck and brain
Left subclavian artery?
From arch of aorta
Supplies left upper limb
What and where are aortic bodies?
In the arch of the aorta
Where chemoreceptors are located…
Monitor arterial pO2 and pCO2
Visceral sensory info travels by vagus nerve
Reflex responses control ventilation
Thoracic aorta?
Below descending aorta…sometimes same thing
Ligamentum arteriosum?
Fibrous cord connection between pulmonary trunk and aortic arch
Remnant of ductus arteriosus from fetus
Ductus arteriosus?
Diverted blood from pulmonary trunk from aortic arch, closes at birth when lungs are used
Superior vena cava(SVC) what and where in thorax
Returns blood from head neck and upper limbs
Union of l/r brachiocephalic veins
SVC and tributaries in superior mediastinum
Brachoicephalic veins both formed how?
Union of internal jugular vein and subclavian vein
Jugular vein?
Drains head and neck
Subclavian vein?
Drains upper limb
Inferior vena cava (IVC) what do
Returns blood from all regions inferior to diaphragm
Abdomen pelvis lwr limbs
Describe IVC in thorax
Thoracic part is short (diaphragm to right atrium)
Describe trachea
Semi-rigid
C- shaped incomplete rings of cartilage in walls
Palpable
Terminates at sternal angle, at carina
What is the carina?
Where the Trachea bifurcates into left and right main bronchi
At sternal angle (junction between T4 and T5 vertebrae)
Where oesophagus
Superior mediastinum- midline of thorax, posterior to Trachea
Posterior mediastinum- it’s there
Oesophagus what do
Waves of contraction from smooth muscles move swallowed food and fluid dismally
(Peristalsis)
What do the lr vagus nerves (CN X) contain?
Somatic fibres
Sensory
Somatic motor
Parasympathetic
Where do lr vagus nerves innervate
Thorax and abdomen structures
Head and neck
Contribute parasympathetic fibres to heart lungs oesophagus
Covey parasympathetic fibres to most abdominal viscera
Path of l/r vagus nerves in the thorax
Descend alongside internal carotid artery and internal jugular vein
Enter thorax by superior thoracic aperture
Give rise to recurrent laryngeal nerve (RLN), innervation larynx back up in neck
Descend into thorax posterior to root of lung (hilum)
Left recurrent laryngeal nerve pathway
Loop under arch of aorta
Ascends back up left of neck alongside Trachea
To larynx
Right recurrent laryngeal nerve (RLN) pathway
Descends anterior to right subclavian artery
Loops under inferior border
Ascends back up right side neck
Between Trachea and oesophagus
What is thoracic duct
Channel for lymphatic drainage for most of body regions
In superior mediastinum empties into venous system at Union of left (internal jugular vein and subclavian)
What is thymus gland
Lymphoid organ
Anterior of superior mediastinum
Atrophies with age, becoming fatty so not in cadevars
Wha tis pericardium
Fibrous sac around the heart
Loose to allow heart movement
2 layers
What are the 2 layers of the pericardium?
Tough outer fibrous layer
Attached superior to great vessels, inferior to central tendon of diaphragm
Thin inner serous layer
Parietal layer lines inner fibrous pericardium
Visceral layer covers heart surface
These 2 continuous with each other
Pericardial cavity explain
Space between 2 serous pericardium layers
Small amount of pericardial fluid for lubrication between 2 as heart moves
What innervation the fibrous pericardium
Sensory branches from lr phrenic nerves
What is the posterior surface of heart?
The base surface also
Faces posteriorly
Corresponds with left atrium mainly
(Part of right atrium)
What is inferior surface of heart?
Also diaphragmatic surface
On central tendon of diaphragm
Corresponds to left ventricle
(Also part right ventricle)
What is anterior surface of the heart?
Also sternocostal surface
Faces sternum and ribs
Corresponds with right ventricle
What is left pulmonary surface of heart?
Face the lung
Corresponds with left ventricle
What is right pulmonary surface of heart?
Face lung
Corresponds with right atrium
What and where is the apex?
Formed by left ventricle
5th intercostal space at midclavicular line
Beat palpable here
What are borders of the heart? When important?
Important for clinical examination, chest X rays
Inc right - right atrium
left - left ventricle
inferior border- right ventricle + part left
Describe right border of the heart
Lateral to right sternal edge
3rd to 6th right costal cartilage
Right atrium
Describe left border of heart
Left midclavicular line
2nd to 5th(@apex) left intercostal space
Left ventricle
Describe the inferior border of the heart
Connects inferior end of right border with the apex
6th costal cartilage to apex
Right ventricle +part left
Superior border of heart
Connects superiors of left and right borders
Right 3rd costal cartilage to left 2nd intercostal space
Auricles?
Auricular appendages
Outpourings from walls of lr atria
Ear like appearance
Patent ductus arteriosus (PDA)
Congenital cardiac anomaly
Ductus arteriosus doesn’t close
Blood flows from aorta to pulmonary trunk due to pressure
Over time leads to Inc pulmonary hypertension (high pressure in lung vessels)
Strains right side of heart
Lung cancer leading to hoarseness of voice
Cancer at apex of lung
May involve RLN
Injury results in weakness/paralysis of ipsilateral intrinsic laryngeal muscles(move larynx and vocal chords)
Patient can’t fully adduct their vocal chords
Pericardial effusion
Pericardial effusion - Inc fluid in pericardial space, maybe from inflammation of pericardium (pericarditus) or accumulation of blood
Cardiac tamponade
Heart is compressed when fluid Inc in pericardial effusion to the point of compressing the heart (fibrous pericardium can’t stretch)
Heart can’t fill properly
