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Flashcards in Anatomy Practical 1 Deck (57):
1

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

2

How does tongue push bolus to the back of the mouth?

Elevates the hard palate using intrinsic muscles of the tongue

3

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

4

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

5

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

6

What is the oesophagus?

fibromuscular tube
2cm diameter
pharynx to stomach

7

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

8

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

9

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

10

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

11

What are the levels of the upper and lower oesophagus?

Upper - C6-T4
Lower - T4-T10

12

What is a crus?

one of two tendinous structures that extends below the diaphragm to the vertebral column

13

What is the costal margin?

lower edge of the chest (thorax) formed by the bottom edge of the rib cage.

14

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

15

What is the most common form of hiatal hernias?

sliding hiatus hernias

16

What is the inguinal ligament?

Thickening of the external oblique aponeurosis spanning from ASIS to pubic tubercle of pelvis

17

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

18

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

19

What does the inguinal canal contain?

Male - spermatic cord and ilioinguinal nerve
Female - round ligament of the uterus and ilioinguinal nerve

20

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

21

How do hernias usually present?

As a lump/mass with/without pain

22

Why are hernias clinically important?

Bowel lumen can become obstructed or strangulated (blood supply in its wall cut off) requiring surgical intervention

23

What are the causes of hernia?

1 - anything raising intra-abdominal pressure (excessive coughing, lifting, heavy weights)
2- anything weakening/stretching abdominal wall (old age, incision from operation, obesity, pregnancy)

24

What are the most common hernias?

Inguinal and femoral

25

What is the femoral canal?

A space found in the femoral triangle
Medial to femoral vein containing lymphatic vessels and lymph gland

26

What are inguinal hernias classified as?

Direct - protrude through abdominal wall (often through Hasselbach's triangle)
Indirect - pass through deep inguinal ring and can extend through inguinal canal out of superficial ring into scrotum

27

What is the peritoneum?

Continuous serous membrane sitting on abdominal cavity lining abdominal viscera completely or partially
Visceral peritoneum covering organs and parietal covering body wall
potential space between 2 layers containing serous fluids allowing organs to slip over one another friction free

28

What are intraperitoneal organs?

Organs engulfed within the peritoneum
positions can vary and are not fixed

29

What are retroperitoneal organs?

Organs which press from behind
In fixed posiitons

30

What are ligaments, mesentery and omentum examples of? What is their function?

Folds - as organs press into peritoneum they form folds providing double layers of peritoneum
- carry nerves, blood vessels, lymphatics and provide support for viscera

31

What is the mesentery?

Folds of visceral peritoneum that arise from posterior abdominal wall and extend to jejunum and ileum

32

What is the mesentery proper?

part of the mesentery suspending the small intestine

33

What is the omentum?

greater and lesser
greater - larger double layer of visceral peritoneum starting from greater curvature of stomach hanging down in front of small intestine then double layer folds back on itself and attaches to back of transverse colon
lesser - double layer of peritoneum extending from liver to lesser curvature of stomach and part of duodenum

34

What does the falciform ligament attach?

Liver, anterior abdominal wall and diaphragm

35

What is laproscopy?

process of viewing inside the abdomen using fibre optic camera

36

What are adhesions?

Inflammation/incisions causes scarring = two layers of peritoneum can stick together and limit movement of internal organs

37

What are the two types of abdominal pain?

visceral pain - layer sparsely innervated hence produces dull, poorly localised pain
parietal pain - richly innervated by somatic nerves, causes well localised sharp pain

38

What does the foregut, midgut and hindgut contain?

Foregut - liver, gall bladder, pancreas, spleen, proximal duodenum
Midgut - distal duodenum, jejunum, ileum, caecum, appendix, ascending colon, 2/3 transverse colon
Hindgut - 1/3 transverse colon, descending colon, sigmoid colon, rectum

39

What are the levels of the foregut, midgut and hindgut?

foregut - T6-T9
midgut - T8-T12
hindgut - T12-L2

40

Where does the thoracic aorta become the abdominal aorta?

T12 when it passes through the diaphragm

41

What is the blood supply to the gut derived from?

Abdominal aorta via 3 main arteries - coeliac trunk, SMA, IMA

42

What are the branches of the SMA?

- branches to jejunum and ileum
- 3 large branches supplying colon
- 15-18 branches to small bowel which unit forming arches

43

What is the marginal artery?

Where the SMA and IMA overlap

44

What is mesenteric ischaemia?

occurs as a result of blockage of blood supply to gut from IMA or SMA due to thrombus/embolus formation causing abdominal pain, vomiting, bloody stool and can result in gangrenous bowel and death if blood supply not restored within 24/48 hrs

45

What is the position of the sigmoid colon?

Starts anterior to pelvic brim, below it is continuous with rectus, intraperitoneal, mobile and forms a loop, attached to posterior pelvic wall by fan shaped sigmoid mesocolon

46

Where does rectum start?

anterior to 3rd sacral vertebra

47

How can a sigmoid volvulus occur?

Sigmoid colon is mobile so can rotate around mesentery, may correct itself spontaneously or rotation may continue until blood supply is shut off, rotation occurs commonly clockwise

48

What is the position of the rectum?

Follows curves of sacrum and coccyx
Ends at tip of coccyx by piercing pelvic diaphragm and becoming continuous with anal canal
Lower 1/3 devoid of peritoneum covering

49

What is the puborectalis?

Portion of levator ani muscle forming a sling at the junction of rectum with anal canal pulling bowel forward producing anorectal angle
blend with deep fibres of external sphincter

50

What blood supply is there to the rectum?

superior, middle and inferior rectal arteries
superior rectal artery is direct continuation of inferior mesenteric artery
middle rectal artery is small branch from internal iliac artery
inferior rectal artery is branch of pudendal artery anastomosing with middle rectal artery at anorectal junction

51

What is the anal canal?

Last part of large intestine
starts at anorectal junction at level of pubo rectalis muscle
split into 2 sections - upper and lower divided by pectinate line

52

What is the upper part of the anal canal?

Originates from the embryological endoderm (hindgut) at the anorectal junction
has anal columns of Morgagni joined by anal valves inferiorly marking inferior border of upper part of anal canal and secrete mucous on defaecation
blood supply and drainage by superior rectal artery and vein

53

How is the innervation different above and below the pectinate line?

above - visceral nerve supply coming from hypogastric plexus, sensitive to stretch
below - somatic, from inferior rectal nerves, sensitive to pain/temp/touch

54

What is the blood supply to the lower half of the anal canal?

Inferior rectal artery
divided into 2 zones separated by Hilton's white line (anal verge)

55

What are the anal sphincters?

Internal - involuntary smooth muscle sphincter supplied by PS fibres passing through pelvic splanchnic nerves, sphincter relaxes in response to pressure distending rectal ampulla
external - voluntary innervated primary by S4 through inferior rectal nerve

56

Where are the anal cushions?

At the level of the pectinate line

57

What are prolapsed haemorrhoids?

Lump around anus, may need to be pushed back or may return to anal canal on their own after bowel movement
some unable to be pushed back and can become extremely painful but haemorrhoids generally not painful
symptoms may also be seen in patients with colorectal cancer