Anatomy Practical 1 Flashcards
What are the phases of eating and swallowing?
1) oral phase: voluntary control (motor cortex and cortical areas)
2) Pharyngeal phase: co-ordinated by swallowing centre in medulla oblangata and pons, reflex initiated by touch receptors in pharynx as bolus of food gets push to back of mouth by tongue
3) oesophageal phase: ANS coordinated
How does tongue push bolus to the back of the mouth?
Elevates the hard palate using intrinsic muscles of the tongue
What is laryngeal closure?
primary laryngopharyngeal protective mechanism to prevent aspiration during swallowing
vocal fold adduction and retroversion of epiglottis
anatomically directs food bolus laterally towards piriform fossa
What is the oesophageal phase?
involuntary neuromuscular control
propagation of food bolus is slower than in pharynx
bolus enters oesophagus and is propelled downwards by striated muscle first then smooth muscle
upper oesophageal sphincter relaxes letting food pass
striated constrictor muscles of pharynx + peristalsis + relaxation of LOS = bolus is pushed through oesophagus into stomach
What are some risk factors for aspiration of foreign materials into the lungs?
- poor gag reflex in unconscious after stroke/brain injury
- drinking large amounts of alcohol
- general anaesthesia
- old age
- swallowing problems
- coma
- being less alert due to medicines, illness
What is the oesophagus?
fibromuscular tube
2cm diameter
pharynx to stomach
What is the position and direction of the oesophagus?
in between trachea and vertebral column
descends in posterior mediastinum passing posterior to right of arch of aorta and left atrium
deviates to left behind pulmonary artery and left bronchus passing through oesophageal hiatus at T10 vertebra to reach stomach
What is posterior, anterior and to the left and right of the upper oesophagus?
Posterior - vertebral column
Anterior - trachea
on both sides - dome of pleura and superior lobe of each lung
What is posterior, anterior and to the left and right of the lower oesophagus?
Posterior - vertebral column
Anterior - heart (LA)
Left - descending thoracic aorta
Right - azygos vein and inferior lobe of right lung
What are the oesophageal sphincters?
UOS -> voluntary skeletal muscle comprised of inferior pharyngeal constrictor/cricopharyngeus
LOS -> specialised segment of circular muscle layer of distal oesophagus, first anti-reflux barrier protecting oesophagus from acidic gastric content
What are the levels of the upper and lower oesophagus?
Upper - C6-T4
Lower - T4-T10
What is a crus?
one of two tendinous structures that extends below the diaphragm to the vertebral column
What is the costal margin?
lower edge of the chest (thorax) formed by the bottom edge of the rib cage.
What is a hiatus hernia?
protrusion of upper part of stomach into thorax through tear/weakness in diaphragm, often result in heartburn but can cause chest pain with eating, most common cause is obesity
What is the most common form of hiatal hernias?
sliding hiatus hernias
What is the inguinal ligament?
Thickening of the external oblique aponeurosis spanning from ASIS to pubic tubercle of pelvis
What is the inguinal canal?
A space passing obliquely through abdominal wall in the inguinal region, found over medial half of inguinal ligament
formed by anterolateral muscles of abdominal wall (external and internal oblique and transversus abdominis) and their aponeuroses
What are the openings of the inguinal canal?
- deep internal ring: opening in transversalis fascia located at midpoint of inguinal ligament, halfway between ASIS and pubic tubercle
- superficial external ring: opening in external oblique aponeurosis, located above pubic tubercle
What does the inguinal canal contain?
Male - spermatic cord and ilioinguinal nerve
Female - round ligament of the uterus and ilioinguinal nerve
What is a hernia?
A protrusion of a tissue/structure/part of an organ through a wall which normally contains it
Areas of abdominal wall may be weak so predisposed to contents protruding through them
How do hernias usually present?
As a lump/mass with/without pain
Why are hernias clinically important?
Bowel lumen can become obstructed or strangulated (blood supply in its wall cut off) requiring surgical intervention