Alimentary System, Nutrition and Metabolism Flashcards
(369 cards)
1
Q
What does the alimentary system consist of (including parts)?
A
Alimentary canal → GIT:
Muscular tube that consists of the oral cavity, pharynx, oesophagus, stomach, small intestine, large intestine and anus.
Accessory digestive organs:
Organs that compliment the alimentary canal (e.g. teeth, tongue, gallbladder and various glandular organs such as salivary glands, pancreas, liver).
2
Q
What is the function of the digestive system?
A
AIDES
Absorption
Ingestion
Digestion (mechanical = oral cavity and chemical = occurs without our control)
Excretion (removal of waste products from the body)
Secretion (release of a substance from a cell or gland)
3
Q
What are the layers of the digestive tract?
A
Deep to superficial = mucosa, submucosa, muscularis and serosa
4
Q
What layers does the mucosa contain?
A
Contains 3 layers: Epithelial lining, lamina propria and muscularis mucosa
5
Q
What is unique about the submucosa?
A
Epithelial lining is avascular so it can get a lot of nutrients and oxygen (through diffusion of the submucosa).
6
Q
What are the types of epithelial lining of the GI tract?
A
Stratified squamous epithelium provides physical protection for the oral cavity, pharynx and oesophagus
Simple columnar epithelium secrete and absorb substances for the stomach, small and large intestine
Stratified squamous epithelium provides physical protection during excretion for the anus
7
Q
What is special about the small intestine?
A
It contains microvilli to increase the surface area for absorption.
8
Q
What are the types of muscles in the alimentary tract?
A
Smooth and skeletal muscles are found in the alimentary canal.
9
Q
What does the Alimentary canal consists of?
A
An incomplete muscular tube (e.g. pharynx) and complete circular tube (e.g. the rest of the alimentary canal).
10
Q
What does the muscularis externa of the alimentary canal consist of?
A
The inner circular and outer longitudinal muscles (except in the pharynx and stomach).
11
Q
What is common in most of the large intestine?
A
Most of the large intestine (except the rectum and anus) have the outer longitudinal band reduced to 3 bands called teniae coli.
12
Q
Define haustra?
A
The circular muscle of the large intestine is folded into pocketlike sacs called haustra.
13
Q
What is adventitia and what does it cover?
A
An outer layer of dense irregular connective tissues to bind organs or vessels together
Found in retroperitoneal organs in the abdominal cavity and cannot move (e.g. ascending and descending colon).
14
Q
What is serosa and what does it cover?
A
A layer of simple squamous cells and thin connective tissue and lines walls of the body cavities (e.g. parietal peritoneum in the abdominal cavity or parietal pleura in the thoracic cavity) where the serous fluid lubricates serous membranes.
Found in intraperitoneal organs in the abdominal cavity and can move (e.g. jejunum, ileum).
15
Q
What is the skull divided into?
A
Neurocranium (8 bones - 4 individual & 2 paired bones)
Viscerocranium (14 bones - 2 individual & 6 paired)
16
Q
What bones form the neurocranium?
A
Unpaired = occipital, frontal, sphenoid and ethmoid bones
Paired = parietal and temporal bones.
17
Q
What bones form the viscerocranium?
A
Unpaired = Vomer & mandible
Paired = maxillae, palatine bones, nasal bones, inferior nasal conchae, zygomatic bones and lacrimal bones.
18
Q
What bones form the anterior, middle and posterior cranial fossa?
A
Anterior = frontal, ethmoid, sphenoid
Middle = sphenoid, temporal
Posterior = occipital, temporal, parietal, sphenoid
19
Q
How is a fossa different to a foramen?
A
Fossa = shallow depression on the surface of a bone
Foramen = hole or opening in a bone
20
Q
A
21
Q
A
22
Q
A
23
Q
What cranial nerves innervate the alimentary system?
A
Cranial nerves V, VII, IX, X, XI, XII
24
Q
Which cranial nerves pass through these structures?
- Foramen rotundum
- Foramen ovale
- Foramen spinosum
- Internal acoustic meatus
- Jugular foramen
- Hypoglossal canal
What cranial nerve passes through the foramen rotundum?
A
- CN V (V2 maxillary)
- CN V (V3 mandibular)
- Middle meningeal artery (branch of the maxillary artery)
- CN VII (facial), VIII (vestibulocochlear)
- CN IX (glossopharyngeal), X (vagus), XI (accessory)
- CN XII (hypoglossal)
25
What is the importance of the jugular notch of the occipital bone?
It is the end of the venous sinuses and the start of the internal jugular vein
26
What is the face?
The anterior aspect of the head from the forehead to the chin and from one ear to the other ear
27
Why do infants have 'puffy cheaks?'
Because of their relatively large buccal fat pads
28
What is common between all the muscle of facial expression?
They are all subcutaneous
29
What are the muscle of facial expression?
Occipitofrontalis
Orbicular Oris, Orbicularis Oculi
Buccinator
Levator Labii Superioris
Depressor Labii Inferioris
Mentalis
Zygomatic Major
Levator Anguli Oris and Depressor Anguli Oris
Risorius
30
1. Occipitofrontalis
2. Orbicularis Oris
3. Orbicularis Oculi
31
1. Buccinator
2. Levator Labii Superioris
3. Depressor Labii Inferioris
32
1. Mentalis
2. Zygomatic Major
3. Levator Angulis Oris
33
1. Depressor Anguli Oris
2. Risorius
34
What are the functional groups of the facial muscles?
Orbital group (palpebral and orbital parts of the orbicularis oculi)
Nasal group (nasalis, procerus)
Oral part (orbicularis oris, buccinator)
35
Identify the orbital group of the facial muscles?
36
Identify the nasal group of the facial muscles?
37
Identify the oral group of the facial muscles?
38
Which facial muscles would be involved in your expressions of happy, surprise, sad and angry?
Happy = Zygomatic major, orbicularis oculi
Surprise = Orbicularis oculi
Sad = Depressor angulis oris, orbicularis oculi
Angry = Depressor anguli oris, orbicularis oris
39
Categorise the following facial muscles (oral part) as sphincters or dilators including their function
Zygomaticus major
Zygomaticus minor
Risorius
Buccinator
Sphincter muscle = Buccinator (active in chewing, keeps cheek taut during chewing, aids mastication)
Dilator muscles = Zygomaticus major (smiley muscle), zygomaticus minor (raise upper lip) and risorius (draws the corner of the mouth laterally when grinning)
40
What is the cutaneous innervation of the face?
41
Which cranial nerve provides motor innervation to the muscles of facial expression? What are the 5 terminal branches?
CN VII (facial)
**Two Zebras Bit My Cat**
Temporal branch
Zygomatic branch
Buccal branch
Marginal mandibular branch
Cervical branch
42
Describe the location of the facial nerve?
Internal acoustic meatus --> passes through the temporal bone --> emerges from the base of the skull through the stylomastoid foramen --> branches off into the posterior auricular nerve (supplies the occipital belly of occipitofrontalis muscle) and posterior belly of digastric muscle and stylohyoid --> branches into the 5 terminal branches at the parotid gland
43
What are the structures within the parotid gland (from superficial to deep)?
1. Facial nerve and its branches
2. Retromandibular vein
3. External carotid artery
44
What is the nerve supply of the parotid gland?
Sensory = Auriculotemporal nerve branch of
mandibular division of trigeminal nerve
Parasympathetic = Glossopharyngeal nerve synpases with the otic ganglion and the auriculotemporal nerve carries parasympathetic fibres to the parotid gland
Sympathetic = Superior cervical ganglion
45
What blood vessels supplies blood to the face?
1. Facial artery (a branch of the external carotid artery)
2. Superficial temporal artery (a terminal branch of the external carotid artery)
***Note: Facial artery supplies most of the blood to the face
46
What are the palpation points of the facial blood vessels?
1. Facial artery palpation
2. Superficial temporal arteries palpation
47
Why is it important that the intracranial and extracranial veins are connected?
Since intracranial veins do not have valves, they must be connected to provide movement of blood in any direction (otherwise blood can move in the opposite direction)
48
What is the 'danger triangle' considered dangerous
Infections in the danger triangle can spread easily to the brain through a network of veins called the cavernous sinus
49
Define the oral cavity?
The space between the anterior and posterior oral aperture
50
What makes up the roof, wall, floor, anterior aperture and posterior aperture of the oral cavity proper?
Roof = Anterior 2/3 of the hard palate and posteriorly the soft palate
Wall = cheeks
Floor = Muscular diaphragm and the tongue
Anterior aperture = Oral fissure (mouth opening)
Posterior aperture = Oropharyngeal isthmus
51
Identify and define the oral vestibule and the oral cavity proper?
Oral cavity proper = The space between upper and lower dental arches to the posterior oral aperture
Oral vestibule = The space between the teeth and buccal gingiva and the lips and cheeks)
52
53
54
1. Mylohyoid muscle
2. Geniohyoid muscle
3. Genioglossus muscle
55
What are the parts of the tongue?
56
Define gingiva?
The tissue of the upper and lower jaws that surrounds the base of the teeth. Also called gums
57
What is the skeletal framework of the oral cavity?
Paired maxillae, mandible and palatine bones
58
Identify the parts of the maxilla?
1. Palatine process
2. Alveolar process
3. Infraorbital foramen
59
60
61
What structure enter the mandibular foramen?
Inferior alveolar artery
Inferior alveolar vein
Inferior alveolar nerve
62
What structure exits the mental foramen?
Mental nerve
63
What are the types of oral mucosa of the oral cavity and where are they found?
1. Masticatory mucosa (gingiva and hard palate = )
2. Lining mucosa (lips, cheeks, alveolar mucosal surfaces, floor of the mouth, soft palate = )
3. Specialised mucosa (dorsum of the tongue)
64
What type of epithelium are found in the different types of mucosal lining of the oral cavity?
Masticatory mucosa = Stratified squamous keratinised epithelium
Lining mucosa = nonkeratinised stratified squamous epithelium
65
What is the terminal sulcus?
Divides the dorsum of the tongue into the anterior 2/3 part covered with relatively thin mucosa with a rough appearance due to numerous lingual papillae and the posterior part has thick mucosal lining and rough due to many lymphatic nodules, forming the lingual tonsil
66
Identify and define papillae?
The little bump on the top of your tongue that help grip food while your teeth are chewing
67
Where are taste buds found?
Are present on fungiform, foliate and circumvallate papillae.
68
Why are some drugs easily absorbed if placed under the tongue?
The tongue is covered by a thin mucous membrane, transparent and visible numerous deep lingual veins
69
What attaches the tongue to the floor of the mouth?
Frenulum
70
71
Name and identify the extrinsic neck muscles?
1. Genioglossus muscle
2. Hyoglossus muscle
3. Styloglossus muscle
4. Palatoglossus muscle
72
What artery and veins supply and drain blood from the tongue?
Lingual artery
Deep lingual vein & dorsal lingual vein
73
Describe the nerve supply of the tongue?
74
What is the nerve innervation of the intrinsic tongue muscles?
CN XII (hypoglossal nerve)
75
Which cranial nerves innervate for the special sensation of taste?
CN VII (facial) - taste in anterior 2/3, CN IX (glossopharyngeal) - taste in posterior 1/3, CN X (vagus) - taste in pharynx and epiglottis
76
1. Temporal bone
2. Mandible
3. (ANTERIOR) Articular tubercle of temporal bone
4. Condylar process of mandible
5. Articular surface of mandibular fossa of the temporal bone
6.
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78
What movement do these ligaments allow at the temporomandibular ligament?
Mandibular depression, elevation, retrusion and protrusion
79
Name and identify the muscles of mastication?
1. Temporalis
2. Masseter
3. Medial pterygoid
4. Lateral pterygoid
80
What is the nerve supply and function of the muscles of mastication?
Nerve supply = CN V,
mandibular division of trigeminal nerve
Function = chewing at the temporomandibular joint
81
Identify the origin, insertion and action of the masseter muscle?
Origin:
Zygomatic arch and maxillary process
of zygomatic bone
Insertion:
Lateral surface of ramus of
mandible
Action:
Elevation of mandible
82
What are the two sets of teeth that erupt during someone's lifetime?
1. Primary teeth (aka milk teeth) - children have 20 deciduous teeth
2. Secondary teeth - adults have 32 teeth
83
Identify the types of permanent teeth?
1. First (central) incisor
2. Second (lateral) incisor
3. Canine
4. First premolar
5. Second premolar
6. First molar
7. Second molar
8. Third molar (wisdom tooth)
84
Identify the eruption of deciduous teeth?
85
Identify the eruption of permanent teeth?
86
87
Through which layers of a molar tooth would an oral surgeon drill to perform a root canal treatment?
Enamel, dentin, pulp cavity
88
Identify the salivary glands?
89
What nerves innervate the salivary glands?
Parotid gland = CN IX (glossopharyngeal)
Sublingual nerve = Chorda tympani nerve (branch of the facial nerve)
Submandibular nerve = Chorda tympani nerve (branch of the facial nerve) and lingual nerve
90
What is the relationship between CN VII and the parotid gland?
Since the facial nerve passes through the parotid gland (even though it doesn't innervate it) any trauma to the parotid gland (aka to the lateral side of their face) will cause the facial nerve to be impacted possibility resulting in lateral facial paralysis
91
Week 2: Swallowing
Week 2: Swallowing
92
What are the boundaries of the neck?
Superior boundary:
Inferior margin of the mandible (anterior) to the superior nuchal line (posterior)
Inferior boundary:
Superior border of the manubrium sterni to the superior border of the clavicla (all anterior) to the C7 vertebrae (posterior)
93
What does the fascia of the neck consist of?
Superficial fascia
Deep fascia
94
Identify the main veins of the neck?
95
What fascia compartments form the deep cervical fascia?
Investing layer
Prevertebral layer
Pretracheal layer
Carotid sheaths (paired)
96
What is the innervation and function of the platysma muscle?
Innervation: Cervical branch of the facial nerve (CN VII)
Function: Straighten the skin over the neck (e.g. men usually use this action when shaving), depress both the mandible and the angle of the mouth
97
What does the investing layer of the deep cervical fascia surround?
Trapezius muscle
Sternocleidomastoid muscle
Submandibular gland
Parotid gland
98
Identify the main internal compartments of the pretracheal fascia?
99
Which muscle group is found in the muscular compartment of the pretracheal fascia (including its function)?
Infrahyoid muscles
Function:
Depress the hyoid bone, except the sternothyroid which depresses the larynx
100
What structures are found in the visceral compartment of the pretracheal fascia?
Thyroid gland
Parathyroid glands
Trachea
Oesophagus
*Note: The 4 parathyroid glands are located on the one thyroid gland and the trachea is anterior (in front of) the oesophagus
101
What does the prevertebral layer of the deep cervical fascia surround?
Cervical vertebrae
Deep back muscles
102
What does the prevertebral layer of the deep cervical fascia fully encompass when extending into the back?
Subclavian artery
Brachial plexus
103
Name what is found in each carotid sheath?
Common carotid artery
Internal jugular vein
Vagus nerve (CN X)
*Note: The carotid sheath is paired, hence, we may have to specify left or right
104
Identify the fascial spaces of the neck?
Pretracheal space = Posterior to the infrahyoid muscles and anterior to the trachea
Retropharyngeal space = posterior surface of the pretracheal fascia
105
Name the superficial neck muscles?
Platysma muscle
Sternocleidomastoid muscle
Platysma muscle
106
Identify the muscle and its attachments?
Sternocleidomastoid muscle
Origin = Manubrium sterni (sternal head) and medial third of the clavicle (clavicular head)
Insertion = Mastoid process of the temporal bone and the superior nuchal line of the occipital bone
107
Identify the nerve supply and function of the SCM?
Nerve supply = Accessory nerve
Function = Flexion of the neck (bilateral contraction), lateral rotation of the neck both ipsilaterally and contralaterally (unilateral contraction)
108
Identify the muscle and its attachments?
Trapezius
Origin = Superior nuchal line & nuchal ligament spinous processes of C7-T12
Insertion = Lateral ⅓ of the clavicle, acromion and spine of the scapula
109
Identify the muscle and its attachments?
Platysma muscle
Origin = Superficial fascia of the thorax
Insertion = Lower border of the mandible
110
Identify the muscle and note its function in respiration?
Accessory muscles of respiration and act by elevating the first two ribs during forced inspiration
111
What clinical relevance would the scalene muscles have in a patient with chronic and severe respiratory disease?
The scalene muscles (accessory muscles of respiration) would aid in inspiration by elevating the first two ribs to compensate for the weakened primary muscle of respiration
112
Identify the suprahyoid muscles?
113
Identify the suprahyoid muscles?
114
Identify the suprahyoid muscles?
115
Identify the attachments, nerve supply and function of the mylohyoid muscle?
Origin = Mylohyoid line of mandible
Insertion = Mylohyoid raphe, body of hyoid bone
Nerve supply = Nerve to mylohyoid
Function = Elevates the hyoid bone, floor of the mouth and tongue during swallowing
116
Identify the attachments, nerve supply and function of the geniohyoid muscle?
Origin = Inferior mental spine (inferior genial tubercle)
Insertion = Body of the hyoid bone
Nerve supply = C1 nerve via hypoglossal nerve
Function = Pulls hyoid bone anterosuperiorly
117
Identify the attachments of the stylohyoid muscle?
Origin = Styloid process of temporal bone
Insertion = Body of hyoid bone
Nerve supply = Facial nerve
Function = Elevates and retracts the hyoid bone
118
Identify the attachments of the digastric muscle?
Origin = Digastric fossa of mandible (anterior belly), mastoid notch of temporal bone (posterior belly)
Insertion = Body of hyoid bone
Nerve supply = Anterior belly (CN V3) and Posterior belly (CN VII)
Function = Depresses mandible and raises hyoid bone
119
Identify the infrahyoid muscles?
120
121
Identify the attachments, nerve supply and function of the sternohyoid muscle?
Origin = Manubrium of sternum, medial end of clavicle
Insertion = Inferior border of body of hyoid bone
Nerve supply = Ansa cervicalis
Function = Depresses hyoid bone
122
Identify the attachments, nerve supply and function of the omohyoid muscle?
Origin = Superior border of scapula near the suprascapular notch (inferior belly), intermediate tendon (superior belly)
Insertion = Intermediate tendon (Inferior belly), body of hyoid bone (superior belly)
Nerve supply = Ansa cervicalis
Function = Depresses, retracts and steadies hyoid bone
123
Identify the attachments, nerve supply and function of the sternothyroid muscle?
Origin = Posterior surface of manubrium of sternum, Costal cartilage of rib 1
Insertion = Oblique line of thyroid cartilage
Nerve supply = Ansa cervicalis
Function = Depresses hyoid bone and larynx
124
Identify the attachments, nerve supply and function of the thyrohyoid muscle?
Origin = Oblique line of thyroid cartilage
Insertion = Inferior border of body and greater horn of hyoid bone
Nerve supply = C1 via hypoglossal nerve
Function = Depresses hyoid bone and elevates larynx
125
Identify the suprahyoid and infrahyoid muscles?
Suprahyoid muscles:
8. Anterior belly of digastric muscle
20. Geniohyoid muscle
21. Mylohyoid muscle
*Stylohyoid not seen on this prosection
Infrahyoid muscles:
23. Superior belly of omohyoid muscle
30. Sternohyoid muscle
31. Sternothyroid muscle
38. Thyrohyoid muscle
126
Identify the anterior and posterior triangles of the neck?
127
Identify the borders of the anterior triangle of the neck?
Superior border = Inferior border of the mandible
Lateral border = Anterior border of the SCM
Medial border = Median line of the neck
128
What are the sub triangles of the anterior triangle of the neck?
1. Submandibular (gastric) triangle
2. Carotid triangle
3. Muscular triangle
4. Submental triangle
129
What structures are located in the submandibular (gastric) triangle?
Submandibular gland
Submandibular lymph nodes
130
What structures are located in the carotid triangle?
Common carotid artery
Bifurcation of common carotid artery
Carotid sinus and carotid body
Internal jugular vein
Vagus nerve
131
What structures are located in the muscular triangle?
Infrahyoid muscles
Thyroid gland
Parathyroid glands
Larynx
132
What structures are located in the submental triangle?
Submental lymph nodes
133
Identify the borders of the posterior triangle of the neck?
Anterior border = Posterior border of the SCM
Posterior border = Anterior border of the trapezius
Inferior border = Middle 1/3 of the clavicle
134
What sub-triangles can be found in the posterior triangle of the neck?
Occipital triangle: Located superiorly, and is named after the occipital bone of the skull
Omoclavicular triangle = Located inferior to the omohyoid muscle and superiorly to the clavicle
135
What can be found in the occipital triangle and supraclavicular triangle of the posterior triangle of the neck?
Occipital triangle = Occipital artery and accessory nerve (CN XI)
Supraclavicular triangle = External jugular vein and the subclavian artery
136
Which muscle separates the occipital and supraclavicular triangles?
Inferior belly of omohyoid muscle
137
Which muscles form the floor of the posterior triangle of the neck?
Splenius capitis
Levator scapulae
Anterior, middleand posterior scalenes
138
Which major vein cross the SCM to enter the posterior triangle of the neck?
The external jugular vein
139
Which muscle passes between these two vessels?
1. Internal jugular vein
2. External jugular vein
Muscle: SCM
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What is the approximate position of the carotid sinus?
Located at the bifurcation of the common carotid artery, which is C3-C4 vertebrae, near the superior border of the thyroid cartilage and found at the proximal part of the internal carotid artery
144
What is the functional importance of the carotid sinus?
Functions as a baroreceptor that helps regulate blood pressure by detecting changes in arterial pressure and initiating reflexes to adjust heart rate and vessel diameter accordingly
145
Identify the branches of the external carotid artery?
146
Identify the branches of the external carotid artery?
147
148
What is the mnemonic for the branches of the external carotid artery?
Some - Superior thyroid artery
Anatomists - Ascending pharyngeal artery
Like - Lingual artery
Freaking - Facial artery
Out - Occipital artery
Poor - Posterior auricular artery
Medical - Maxillary artery
Students - Superficial temporal artery
149
Identify the artery branch from the external carotid artery?
Superior thyroid artery
150
Identify the artery branch from the external carotid artery?
Occipital artery
151
Which cranial foramina does the internal carotid artery pass through to enter the skull?
Foramen lacerum
152
Which region of the skull does the internal carotid artery supply?
Frontal lobe, parietal lobe, temporal lobe and eyes
153
Identify the main branches of the subclavian artery?
154
What does the internal carotid artery and vertebral artery have in common?
Both arteries supply blood to the brain and contribute to the formation of the Circle of Willis
155
Identify the contents in the carotid sheath?
156
What is the function of C1-C4 anterior rami?
C1-C4 combine to form the cervical plexus which serves skin and muscles of the head, neck, superior chest/shoulders and the diaphragm
157
Which nerve innervates the diaphragm and what spinal roots contribute?
Phrenic nerve, which originates from the spinal roots of C4, C4 and C5
158
Identify the parts of the pharynx from a sagittal view?
159
Where does the pharynx start and end?
Starts from the base of the skull and ends at the inferior border of the cricoid cartilage anteriorly and C6 vertebra posteriorly
160
What are the boundaries of the nasopharynx?
Superior border = Sphenoid and occipital bones
Inferior border = Soft palate
Anterior border = Choanae
Posterior border = C1 and C2 vertebra
161
What are the boundaries of the oropharynx?
Superior border = Soft palate
Inferior border = Superior border of the epiglottis
Anterior border = Oropharyngeal isthmus
Posterior border = C2 and C3 vertebra
162
What are the boundaries of the laryngopharynx?
Superior border = Upper border of the epiglottis
Inferior border = Lower border of the cricoid cartilage
Anterior border = Laryngeal inlet
Posterior border = C3-C6 vertebra
163
Identify structures in the nasopharynx?
1. Pharyngeal tonsil
2. Lingual tonsil (not part of the nasopharynx)
3. Eustachian/pharyngotympanic tube opening
164
What does the pharyngotympanic tube connect?
Connects the middle ear to the nasopharynx
165
Identify the following structure in the oropharynx?
Palatine tonsil
166
Identify the following structure in the oropharynx?
Vallecula recess
167
Identify the following structure in the oropharynx?
Soft palate
*Note: The soft palate is the only structure in the image that is part of the oropharynx
168
Identify the following structure in the laryngopharynx?
Piriform recess
169
Identify the following structures in the laryngopharynx?
*Note: The laryngeal inlet is the opening from the pharynx into the larynx
170
Identify the following circular pharyngeal muscles?
a. Superior constrictor muscle
b. Middle constrictor muscle
c. Inferior constrictor muscle
171
Identify the general origin of the circular muscles of the pharynx?
Pharyngeal raphe
172
What is the nerve supply and function of the circular muscles of the pharynx?
Nerve supply = Pharyngeal plexuses formed by the pharyngeal branch of the vagus nerve, glossopharyngeal nerve and cervical sympathetic nerves
Function = Propel bolus of food to the oesophagus
173
Identify the following circular pharyngeal muscles?
174
Where do stylopharyngeus, palatopharyngeus and salpingopharyngeus each originate from?
Stylopharyngeus = Styloid process of the temporal bone
Palatopharyngeus = Posterior border of the hard palate
Salpingopharyngeus = cartilaginous part of the auditory tube
175
What is the nerve supply and function of the longitudinal muscles of the pharynx?
Stylopharyngeus muscle:
Nerve supply = Glossopharyngeal nerve
Salpingopharyngeus muscle:
Nerve supply = Pharyngeal plexus
Palatopharyngeus muscle:
Nerve supply = Pharyngeal plexus
*Note: All these muscles have the same function - to elevate the pharynx and larynx during swallowing
176
What does salpingo- mean?
Relating to the Eustachian tube
177
Identify the regions of the oesophagus?
178
Name the structures that lie anterior, posterior, superior and inferior to the oesophagus?
Anterior = Trachea and heart
Posterior = Vertebral column and thoracic duct
Superior = Pharynx and larynx
Inferior = Stomach and diaphragm
179
What vertebral level does the oesophagus pass through the diaphragm?
T10 vertebra
180
What other structures pass through the diaphragm and what are their vertebral levels?
Caval hiatus (inferior vena cava and terminal branches of the right phrenic nerve) = T8 vertebra
Oesophageal hiatus (oesophagus, left and right vagus trunks, oesophageal branches of the gastric vessels and lymph vessels) = T10 vertebra
Aortic hiatus (aorta, thoracic duct, azygos vein) = T12 vertebra
181
What bony and muscular structures form the boundaries of the abdominopelvic cavity?
Superior boundary = Thoracic diaphragm
Inferior boundary = Pelvic diaphragm
Anterior boundary = Rectus abdominis, external oblique, internal oblique and transversus abdominis
Posterior boundary = Lumbar vertebrae, psoas major and quadratus lumborum
Lateral boundary = External oblique, internal oblique, transversus abdominis
182
Identify parts of the diaphragm?
183
Identify parts of the cadaveric diaphragm?
1.Oesophageal hiatus
2.Aortic hiatus
8.Caval hiatus
184
Describe the position of the diaphragm?
Separates the thoracic and abdominopelvic cavities
185
Describe the attachments of the diaphragm?
Anteriorly = Xiphoid process of the sternum
Laterally = Costal cartilages of ribs 7 to 10
Posteriorly = Ribs 11 and 12, L3 vertebrae (left crus) and L4 vertebrae (right crus)
186
Describe the action of the diaphragm?
Primary muscle of inspiration and contracts to increase thoracic volume and decrease intrathoracic pressure
187
Which three structures move through the diaphragm?
Oesophagus via the oesophageal hiatus (T10)
Inferior vena cava via the caval hiatus (T8)
Aorta via the aortic hiatus (T12)
188
What is located in the hiatuses that pierce the diaphragm?
Caval (T8) = Inferior vena cava, right phrenic nerve
Oesophageal (T10) = Oesophagus, right and left vagus nerve, oesophageal branches of the left gastric vessels and lymphatic vessels
Aortic (T12) = Aorta, thoracic duct, azygos vein and sympathetic trunk
189
Why is it important the the inferior vena cava passes through the central tendon of the diaphragm?
The central tendon ensures that the inferior vena cava is always kept patent (aka unable to close and obstruct venous blood return)
190
What is the difference between the true and false pelvis?
True pelvis (lesser pelvis) = The space enclosed by the bony pelvis and contains the pelvic organs (e.g. bladder and reproductive organs)
False pelvis (greater pelvis) = The space above the pelvic inlet, which supports the lower abdominal viscera
191
How can you differentiate between a male and female bony pelvis?
192
Identify the structure and explain what its name means?
"White line" in Latin
193
Identify the abdominal muscles and list the muscles from superficial to deep?
1. Rectus abdominis muscle
2. External abdominal oblique muscle
3. Internal abdominal oblique muscle
4. Transversus abdominis muscle
5. Pyramidalis muscle (present in 80% of people)
194
Identify the parts that contribute the abdominal wall from superficial to deep?
1. Superficial fascia-fatty later (Camper's fascia)
2. Superficial fascia-membranous layer (Scarpa's fascia)
3. External oblique muscle
4. Internal oblique muscle
5. Transversus abdominis muscle
6. Transversalis fascia
7. Extraperitoneal fascia
8. Parietal peritoneum
195
What does the superficial fascia of the anterolateral abdominal wall below the umbilicus consist of?
A fatty and membranous layer
196
Identify the orientation and function of the abdominal muscle fibres?
Rectus abdominis = Vertical fibres; flexes trunk
External oblique muscle = Hands in pocket fibres; rotation and lateral flexion
Internal oblique muscle = Hands on chin; assists external oblique
Transversus abdominis = Horizontal fibres; compresses abdominal contents
197
What is the general function of the abdominal muscles?
Support the trunk
Allow movement (flexion and lateral flexion of the trunk)
Hold organs in place
Can increase intra-abdominal pressure for exhalation and defecation
198
What is this bony feature?
Arcuate line (aka semicircular line of Douglas)
199
How does the layering of muscles and fascia change above and below the arcuate line?
The anterior and posterior layers of the rectus sheath are located above the arcuate line, but only the anterior layer of the rectus sheath is located below the arcuate line
200
What is the clinical relevance of the change in structure above and below the arcuate line?
The absence of a posterior layer of the rectus sheath below the arcuate line causes the lower abdominal area to be weaker than the higher abdominal area
This makes it easier for abdominal muscles to bulge/protrude through the lateral edge of the rectus sheath, which increases the chance of developing a 'Spigelian hernia'
201
What is the blood supply of the anterolateral abdominal wall?
Superior epigastric artery & musculophrenic artery (branch of the internal thoracic/mammary artery)
Inferior epigastric artery & deep circumflex iliac branches (branch of the external iliac artery)
Anterior branches of the posterior intercostal arteries
202
Where would you find the blood vessels that supply the anterolateral abdominal wall?
Superior epigastric artery = Between the posterior surface of the rectus abdominis muscle and the posterior layer of the rectus sheath
Inferior epigastric artery = Between the transversalis fascia and the peritoneum
203
Identify the nerve supply of the anterior abdominal wall?
Anterior rami of the T7-T11 spinal nerves
T12 - subcostal nerve
L1 - iliohypogastric nerve & ilioinguinal nerve
204
Identify the dermatomes of the anterior abdominal wall?
T4 spinal nerve: At the level of the nipples (in males)
T10 spinal nerve: Around the umbilicus
T12 spinal nerve: Suprapubic area
L1 spinal nerve: Inguinal region
205
Define an intraperitoneal and retroperitoneal organ?
Intraperitoneal organ = An organ that is completely or almost completely covered by peritoneum
Retroperitoneal organ = An organ that is partially covered by peritoneum and is posterior to the intraperitoneal organs
206
What epithelium is peritoneum made of?
Mesothelium; simple squamous epithelium
207
What is the function of peritoneum?
Lubrication of the abdominal walls and viscera for smooth movement
208
What are the parts of the peritoneum and what do they line?
A = Parietal peritoneum; lines the abdominal and pelvic walls and the inferior surface of the diaphragm
B = Visceral peritoneum; lines the abdominal organs in the peritoneal cavity
209
What is unique about parietal and visceral peritoneum?
Parietal peritoneum = Sensitive to pain and pain is sharp, well localised (with an exception)
Visceral peritoneum = Insensitive to pain, but is sensitive to stretch and chemical irritation and pain is dull, poorly localised and referred
210
What is the exception for pain being well localised for parietal peritoneum?
Pain is not well localised at the roof of the abdominal cavity (aka inferior surface of the diaphragm) because the C3-C5 roots of the phrenic nerve innervate this region and other regions such as the neck and should region, leading to the potential for referred pain from visceral structures
211
Name the digestive organs that are intraperitoneal?
SALTD SPRSS:
Stomach
Appendix
Liver
Transverse colon
Duodenum (first part)
Small intestine (jejunum and ileum)
Pancreas (only tail)
Rectum (upper third)
Spleen
Sigmoid colon
212
Name the digestive organs that are retroperitoneal?
SAD PUCKER:
Suprarenal (adrenal) glands
Aorta and inferior vena cava
Duodenum (except the proximal 2cm)
Pancreas (except the tail)
Ureters
Colon (ascending and descending)
Kidneys
Eosophagus
Rectum
213
What is a mesentery?
A mesentery is a fold of peritoneum that suspends the intraperitoneal organs (organs completely or almost completely covered with peritoneum) and them to the abdominal wall
214
215
Identify this structure and its ligaments?
Lesser omentum
216
Identify this structure and its ligaments?
Greater omentum
217
Identify this structure?
Falciform ligament of the liver
218
Identify the types of mesentery?
a. Mesentery of the small intestine (ileum and jejunum)
b. Mesentery of the transverse colon (large intestine)
c. Mesentery of the sigmoid colon (large intestine)
d. Mesentery of the appendix is not visible from this photo
219
Identify these two structures?
*Note: The lesser sac is also called 'omental bursa/
220
221
What landmark separates the supracolic and infracolic subdivisions?
The transverse colon and transverse mesocolon separate the peritoneal cavity into the supracolic and infracolic compartments
222
What landmark separates the right and left intracolic compartments?
The root of the mesentery of the small intestines
223
Why are the paracolic gutters clinically significant?
Because they are fluid pathways for infection to spread
224
What is the relationship between the parietal and visceral peritoneum?
They are continuous with one another
225
Name the digestive organs that are derived from the foregut?
GI tract organs:
Abdominal part of the oesophagus
Stomach
First and superior half of descending duodenum (part of the small intestine)
Accessory digestive organs:
Liver
Gallbladder
Pancreas
226
Name the digestive organs that are derived from the midgut?
GI tract organs:
Descending duodenum (part of the small intestine)
Transcending duodenum (part of the small intestine)
Ascending duodenum (part of the small intestine)
Jejunum (part of the small intestine)
Ileum (part of the small intestine)
Caecum (part of the large intestine)
Ascenging colon (part of the large intestine)
Proximinal 2/3 of the transverse colon (part of the large intestine)
227
Name the digestive organs that are derived from the hindgut?
GI tract organs:
Distal 1/3 of the transverse colon (part of the large intestine)
Descending colon (part of the large intestine)
Sigmoid colon (part of the large intestine)
Rectum (part of the large intestine)
Superior part of the anal canal - superior to the pectinate line (part of the large intestine)
228
Identify features of the stomach?
229
Identify features of the stomach?
230
How does the epithelium change when entering the stomach?
Changes from non-keratinised stratified squamous epithelium to simple columnar epithelium
The epithelium invaginates into lamina propria forming gastric pits
231
Name this structure and identify its boundaries?
Epiploic foramen (foramen of Winslow)
Superior boundary = Liver
Inferior boundary = First part of the duodenum
Anterior boundary = Hepatic artery and bile duct
Posterior boundary = Inferior vena cava
232
Identify the blood supply of the stomach?
Celiac trunk gives off 3 main branches, common hepatic artery, splenic artery and left gastric artery, all of which contribute to the blood supply of the stomach
233
Identify the venous drainage of the stomach?
*Note: The veins of the stomach follow distribution of the arteries to return the venous blood to the portal system of veins
234
Identify the nerve supply of the stomach?
Nerve supply to the stomach originates from the autonomic nervous system:
Sympathetic = Greater thoracic splanchnic nerve from T6-T9 segments of the spinal cord
Parasympathetic = Vagus nerve (anterior and posterior vagal trunks)
235
Which of the embryological divisions of the 'gut' develop into structures of the alimentary system and respiratory system?
Foregut
Alimentary system = Oesophagus, stomach and parts of the duodenum
Respiratory system = Trachea and lungs
236
Which part of the colon is supplied by the superior mesenteric artery?
Ascending colon
237
Identify the parts of the small intestine?
238
At what vertebral level is each part of the duodenum located?
Superior (1st part) = L1 vertebrae
Descending (2nd part) = L1-L3 vertebrae
Horizontal (3rd part) = L3 vertebrae
Ascending (4th part) = L2 vertebrae
239
240
What do the major and minor duodenal papilla open into?
Major duodenal papilla = Opening of the hepato-pancreatic ampulla (where the common bile duct and and pancreatic duct drains
Minor duodenal papilla = Opening of the accessory pancreatic duct
241
Compare the following characteristics between the jejunum and ileum?
242
Identify the parts of the large intestine?
243
Describe the position and purpose of the ileocecal valve?
Located where the ileum of the small intestine meets the caecum of the large intestine
Its purpose is to prevent reflux/backflow of food from the caecum back into the ileum
244
What is the relationship between the caecum and vermiform ('worm-like') appendix?
The vermiform appendix is a narrow, tube-like structure that extends from the posteromedial wall of the caecum, and is though to have an immunological function due to its lymphoid tissue
245
What is the significance of identifying the McBurney's point?
McBurney's point is 1/3 of the way from the right ASIS to the umbilicus and is used as a guide to locate the position of the appendix
The McBurney point is the most common site of maximum tenderness in acute appendicitis, which is typically determined by the pressure of one finger
246
Identify these structures of the large intestine and explain their significance?
Haustra ('buckets' in Latin) = Slow down the movement of digested matter and facilitate water absorption by mixing the chyme
Taeniae coli = Create the haustra (pouches) when they are contracted and play a role in moving fecal matter through the large intestine
247
What are the four abdominal quadrants and name the lines which divide these spaces?
Median line
Transumbilical line
248
What organs and structures are found in each quadrant?
Left upper quadrant = Stomach, spleen
Right upper quadrant = Liver, gallbladder
Left lower quadrant = Sigmoid colon
Right lower quadrant = Caecum, appendix
249
Identify the abdominal regions and name the organs and structures found in each region?
250
Name the lines which divide the abdominal regions?
Two horizontal lines = Subcostal line (passes just below the 10th rib and transtubercular line (passes through the iliac tubercles)
Two vertical lines = Left and right midclavicular lines (run from the midpoints of the clavicles down to the inguinal region)
251
Identify the muscles of the posterior abdominal wall?
252
What is the 'bony landmark' of the posterior abdominal wall muscles?
Iliac crest (quadratus lumborum origin)
12th rib (quadratus lumborum insertion)
Transverse processes of T12 and L1-L5 (psoas major origin)
Lesser femoral trochanter (psoas major insertion)
253
?
QUADRATUS LUMBORUM:
Origin = Iliac crest and iliolumbar ligament
Insertion = Inferior surface of the 12th rib
Function = Extension of the lumbar spine, lateral flexion of the lumbar spine and stabilises the 12th rib during respiration
254
?
PSOAS MAJOR:
Origin = Transverse processes of T12 and L1-L5
Insertion = Lesser femoral trochanter
Function = Flexion of the hip and lateral flexion of the lumbar spine
255
Identify the parts of the pancreas?
*Note: Uncinate = 'hook'
256
What is the physical relationship of the pancreas and duodenum?
The head of the pancreas lies within the C-shaped curve of the duodenum, while the uncinate process of the pancreas extends posteriorly behind the superior mesenteric vessels
257
What are the endocrine and exocrine functions of the pancreas?
Endocrine function (aka islet of langerhands) = Produces hormones like insulin and glucagon to regulate blood sugar
Exocrine function (acinar and duct tissue) = Secreting digestive enzymes (e.g. amylase, lipase and proteases) into the small intestine
258
Identify the lobes of the liver?
259
What are the two main surfaces of the liver?
Diaphragmatic surface = Anterosuperior surface of the liver, is smooth and convex and is in contact with the diaphragm
Visceral surface = Posteroinferior surface of the liver, is irregular and flat and is in contact with surroundings organs (e.g. stomach, gallbladder and right kidney)
260
What is the bare area of the liver?
The region on the diaphragmatic surface where the liver lacks peritoneal covering and is directly contacting the diaphragm and inferior vena cava
261
262
Identify the recesses (2) of the liver?
263
Identify the recesses (3) of the liver?
264
Identify the collection of blood vessels in the inferior liver?
265
Which ligaments attach the liver to the anterior abdominal wall, stomach, and duodenum?
Falciform ligament = Connects the anterior surface of the liver to the anterior abdominal wall
Hepatogastric ligament = Connects the liver to the lesser curvature of the stomach
Hepatoduodenal ligament = Connects the liver to the duodenun
266
Identify the parts of the biliary tree?
267
Identify the parts of the biliary tree?
268
Describe the position of the spleen in the abdomen – which quadrant and region?
Region = Left hypochondriac region
Quadrant = Left upper quadrant
*Position = between ribs 9-11
269
Identify the main features of the spleen?
Hilus = Contains the blood vessels of the spleen (short gastric vessels, splenic artery, left gastromental vessels and splenic vein)
Diaphragmatic surface = Posterolateral aspect of the spleen, smooth and convex and faces the diaphargm
Visceral surface = Anteromedial aspect of the spleen, concave and is in contact with other organs such as the stomach, colon, pancreas and left kidney
270
How can you tell the difference between a spleen and a kidney?
Spleen = In the left hypochondriac region, is a soft wedge-shaped organ and has a dull percussion sound
Kidney = Left lumbar region, is a bean-shaped organ and has a resonant percussion sound
271
Identify the veins of the GIT?
272
Identify the inferior branches of the IVC?
273
Identify and explain the clinical implications of the difference between the left and right gonadal veins?
Right gonadal vein drains directly into the IVC and the left gonadal vein drains into the left renal vein before draining into the IVC
Increased venous pressure of the left gonadal vein (due to the additional drainage step) can lead to left-sided varicocele (dilated testicular veins)
274
Identify and explain the clinical implications of the difference between the left and right renal veins?
Right renal vein drains directly into the IVC and the left renal vein passes anterior to the abdominal aorta, between the aorta and superior mesenteric artery before draining into the IVC
The left renal vein can be compressed between the aorta and SMA, causing nutcracker syndrome (compression of the left renal vein between the aorta and SMA), which can lead to flank pain, pelvic pain and blood in the urine (aka hematuria)
275
Identify and explain the clinical implications of the difference between the left and right common iliac veins?
The right common iliac artery crosses over the left common iliac vein, potentially compressing it
This compression can cause May-Thunder syndrome, leading to deep vein thrombosis (blood clot forming in a deep vein) in the left-lower limb due to venous stasis
276
Identify the major veins of the GIT (excluding the IVC)?
277
Where do the superior and inferior mesenteric veins drain and what is the physiological purpose of this?
Both the SMV and IMV drain into the hepatic portal vein which directs blood to the liver for processing (e.g. metabolism and detoxification) before it enters systemic circulation
*Note: Neither the SMV or IMV drain into the IVC
278
279
(Hepatic) portal vein
280
What is this plane and what anatomical structures does it transect?
Transpyloric plane
Transects = Pylorus of the stomach, 1st part of the duodenum, duodenojejunal flexure, root of the transverse mesocolon, fundus of the gallbladder, neck of the pancreas, origin of the superior mesenteric artery, commencement of the portal vein, hila of the kidneys and hilum of the spleen
281
What is the location and clinical significance of the transpyloric plane?
Location = Approximately halfway between suprasternal notch and the upper border of the pubic symphysis - roughly at the level of L1
Clinical significance = Is used as a landmark in abdominal imaging and surgery
282
What are the surface projection and palpation sites of the liver?
Surface projection = 5th rib (upper border of the liver) and the right costal margin (lower border of the liver)
Palpation sites = Right costal margin during deep inspiration
283
What are the surface projection and palpation sites of the gallbladder?
Surface projection = Intersection of the right midclavicular line and the tip of the 9th costal cartilage
Palpation sites = Intersection of the right midclavicular line and the right costal margin
284
Identify the main arteries in the abdominal region?
1. Abdominal aorta
2. Left renal artery
3. Left gonadal artery
4. Right common iliac artery
5. Left and right internal iliac arteries
6. Right external iliac artery
285
Identify the branches of the abdominal aorta?
1. Celiac trunk
2. Superior mesenteric artery
3. Inferior mesenteric artery
286
What organs do the branches of the abdominal aorta supply blood to?
Celiac trunk = Stomach, spleen, liver, gallbladder, proximal 1/3 of the pancreas, distal esophagus and the first 1/4 of the duodenum (foregut)
Superior mesenteric artery = Distal 3/4 of the duodenum, distal 2/3 of the head of the pancreas, duodenum, jejunum, ileum, caecum, ascending colon and the proximal 2/3 of the transverse colon (midgut)
Inferior mesenteric artery = Distal 1/3 of the transverse colon, descending colon, sigmoid colon and proximal 2/3 of the rectum (hindgut)
287
What are the vertebral levels of the arteries branching from the abdominal aorta?
Celiac trunk = T12
Superior mesenteric artery = L1
Inferior mesenteric artery = L3
288
Identify the branches of the celiac trunk?
289
Identify the branches of the celiac trunk?
290
Name the branches of the celiac trunk that provide blood supply to the foregut?
Splenic artery = Spleen, pancreas and fundus of the stomach
Left gastro-omental artery = Greater curvature of the stomach
Left gastric artery = Lesser curvature of the stomach
Common hepatic artery = Liver, stomach, pancreas and duodenum (via its branches)
Right gastric artery = Lesser curvature of the stomach
Gastroduodenal artery = Duodenum and pancreas (via superior pancreaticoduodenal artery)
Right gastro-omental artery = Greater curvature of the stomach
Proper hepatic arteries = Liver (via left and right hepatic arteries)
Left and right hepatic arteries = Left and right lobes of the liver
291
Identify the following arteries originating from the celiac trunk?
292
Identify the branches of the superior mesenteric artery?
293
Name the branches of the superior mesenteric artery that provide blood supply to the midgut?
Jejunal arteries = Jejunum
Ileal arteries = Ileum
Ileocolic artery = Distal ileum, caecum and appendix
Right colic artery = Ascending colon
Middle colic artery = Proximal 2/3 of the transverse colon
294
Identify the branches of the inferior mesenteric artery?
295
Identify the branches of the inferior mesenteric artery?
296
Identify the branches of the inferior mesenteric artery?
297
Name the branches of the inferior mesenteric artery that provide blood supply to the hindgut?
Left colic artery = Distal 1/3 of the transverse colon and descending colon
Sigmoid arteries = Sigmoid colon
Superior rectal arteries = Proximal 2/3 of the rectum
298
What is the boundary of SMA versus IMA supply?
Left colic flexure (aka splenic flexure)
299
What is the distal boundary of IMA blood supply? What is the clinical relevance of this? (Hint: pharmacology)
The superior rectal artery (branch of the IMA) supplies blood to the proximal 2/3 of the rectum, where blood is then drained into the portal venous system to undergo first-pass metabolism
The middle and inferior rectal arteries (branch of the internal iliac artery) supply blood to the distal 1/3 of the rectum, where blood is then drained directly into systemic circulation, bypassing first-pass metabolism
300
What are the functions of the liver?
1. Produces and excretes bile
2. Synthesis of plasma proteins and clotting factors
3. Metabolism of fats, proteins and carbohydrates
4. Storage of glycogen, vitamins and minerals (iron)
5. Detoxification
6. Excretion of bilirubin, cholesterol, hormone and drugs
301
Explain the position of the liver at rest, inspiration and full expiration?
Lies in the right hypochondrium and partially in the epigastric region and left hypochondrium
302
Where does the visceral peritoneum not cover the surface of the liver?
Bare area and in the fossa for the gallbladder
303
What is the falciform ligament and round ligament (ligamentum teres hepatis) a remnant of?
Falciform ligament = Remnant of the ventral mesentery of the developing gut
Round ligament = Remnant of the umbilical vein that was carrying well oxygenated blood from the placenta to the foetus
304
Identify this structure and what is its importance?
Ligamentum venosum
Is a fibrous remnant of the foetal ductus venosus and serves as an important anatomical landmark and source of controlling the left hepatic vein during liver dissections that require control of the vessel
305
306
307
Identify the features of the pelvic inlet?
308
Identify the borders of the pelvic inlet?
Anterior border = Pubic symphysis
Posterior border = Sacral promontory
Lateral border = Iliopectineal line
309
Identify the features of the pelvic outlet?
310
Identify the borders of the pelvic outlet (lesser/true pelvis)?
Anterior border = Pubic arch
Posterior border = Tip of the coccyx
Lateral border = Ischial tuberosity and the sacrotuberous ligament
311
Name the walls of the pelvic cavity?
Antero-inferior wall = Body and rami of pubic bone and pubic symphysis
Laterall wall = Obturator foramen closed by obturator internus muscle and its fascia
Posterior wall = Anterior sacroiliac ligament, sacrospinous ligament, sacrotuberous ligament and piriformis muscle
312
Identify features of the pelvic diaphragm?
313
Identify muscles and features of the pelvic floor?
314
What is the function of the (3) levator ani muscles?
1. Supports the abdominopelvic viscera
2. Resists increases in intra-abdominal pressure
3. Helps to hold the pelvic viscera in position
315
What is the nerve supply of the muscles in the pelvic floor?
Piriformis = Ventral rami of S1 and S2
Obturator internus = Nerve to obturator internus
Coccygeus = Ventral rami of S4 and S5
Levator ani = Nerve to levator ani (ventral rami S4 and inferior rectal nerve)
316
What are the triangles forming the peritoneum and what do they contain?
Anterior = Urogenital triangle (contains roots of the penis and scrotum in males and external genitalia in females)
Anal triangle = Anal triangle (contains the anus)
317
Identify this structure and explain its function?
Perineal body:
A fibromuscular mass of tissue that provides stability for the pelvic and perineal structures
318
Identify this structure and explain its function?
Ischio-anal fossa:
A fat-filled space in the perineum that allows for expansion/distension of the anal canal/anus during defecation
319
320
What does the pelvic cavity contain?
--> Rectum and anal canal (terminal parts of the alimentary system)
--> Ureters and urinary bladder (terminal parts of the urinary system)
--> Pelvic genital organs, blood vessels and nerves
--> Ileum of the small intestine, sigmoid colon and transverse colon of the large intestine (organs of the abdominal cavity)
321
Identify the reflection of the peritoneum in females?
322
Identify the reflection of the peritoneum in males?
*Note: The recto-uterine pouch is the lowest point of the peritoneal cavity and is also called the 'pouch of Douglas'
323
Identify the pouches (reflections of the peritoneum folds)?
1. Rectovesical pouch (males)
2. Rectouterine pouch (pouch of Douglas - females)
3. Vesicouterine pouch
324
Where does the rectum start and what is unique about the rectum?
Level of S3 vertebra at the rectosigmoidal junction
The rectum does not contain teniae coli (which is seen in the rest of the large intestine/colon)
325
Identify this structure of the rectum?
*Note: Flexure is a bend/curve in the rectum
326
What is the importance of the anorectal flexure of the rectum?
Faecal continence, which is the ability to control bowel movement and prevent the involuntary passage of stool or gas from the anus
327
Identify the important features of the rectum?
328
What is the function of the rectal ampulla?
Receives and holds an accumulated faecal masses until it is expelled during defecation
329
Explain the histology of the rectum?
--> Histology of the rectum is similar to the histology of the rest of the large intestine/colon
--> Goblet cells are highly present
--> Glands are simple tubular
330
What is the blood supply of the rectum?
Superior rectal artery (terminal branch of the inferior mesenteric artery) = Supplies the proximal half and middle of the rectum
Middle rectal artery (branch of the internal iliac artery) = Supplies the middle and lower part of the rectum
Inferior rectal artery (branch of the internal pudendal artery) = Supplies the distal part of the rectum
331
Identify the arteries supplying blood to the rectum?
332
Identify the veins draining blood from the rectum?
333
What is this organ and describe its location?
Anal canal:
It commences at the narrowing of the rectal ampulla, terminates at the anus and is surrounded by the internal and external anal sphincters
334
Identify the parts of the rectum?
335
Describe the internal anal sphincter?
--> Involuntary
--> Innervated by parasympathetic fibres that passed through the pelvic splanchnic nerves
--> Tonically contracted most of the time to prevent leakage of fluids or flatus
336
Describe the external anal sphincter?
--> Voluntary
--> Receive nerve innervation from the pudendal nerve (a branch of the inferior rectal nerves originating from the ventral rami of S4)
337
Identify the parts of the rectum and explain their relationship?
Anal columns of Morgagni (longitudinal ridges inside the upper part of the anal canal) --> connected at the bottom by anal valves --> which form small pockets called anal sinuses
338
What is the function of anal sinuses?
These pockets contains glands that release mucus, which help to lubricate the anal canal during defecation
339
What is the importance of the dentate (pectinate) line?
Indicates the boundary between the upper and lower segments of the anal canal
340
Identify the difference in epithelium of the rectum and anal canal?
Rectum = Simple columnar epithelium with simple tubular glands
Below the line = Stratified squamous non-keratinised epithelium with no glands (until the pectinate line) and becomes simple columnar epithelium below the pectinate line
341
Identify anatomical features above the pectinate line in the anal canal?
--> Blood supply from the superior rectal artery (branch of the inferior mesenteric artery)
--> Venous drainage into the portal venous system
--> Simple columnar epithelium
--> Nerve supply by the autonomic hypogastric plexuses
--> Sensitive to touch
342
Identify anatomical features below the pectinate line in the anal canal?
--> Blood supply from the middle and inferior rectal arteries
--> Venous drainage is into the systemic venous system
--> Stratified squamous epithelium
--> Nerve supply by the pudendal nerve
--> Sensitive to pain, touch and pressure
343
Explain the lymph drainage of the rectum and anal canal?
Upper rectum = Lymph follows the course of the inferior mesenteric artery and drains into the preaortic lymph nodes
Lower rectum & anal canal above the pectinate line = Lymph follows the middle rectal vessels and drains into the internal iliac lymph nodes
Anal canal below the pectinate line = Lymph drains into the superficial inguinal lymph nodes
344
345
Explain the neural regulation of the GIT?
The enteric nervous system is a complex network of neurons and nerve plexuses within the walls of the GIT (oesophagus to the anal canal) that control digestive functions and work independently of the brain and spinal cord
346
What are the 'interstitial cells of Cajal (ICC)' and what are their function?
ICC are specialised, non-neural cells that are the pacemakers of the GIT, where they generate slow waves that drive rhythmic contractions and also mediate neurotransmission between nerves and smooth muscle
347
What are the plexuses in the GIT, where are they located and what is their function?
Myenteric plexus (Auerbach's plexus):
Found between the longitudinal and circular masses of the muscularis externa layer of the gut wall and controls the movement of smooth muscle
Submucosal plexus (Meissner's plexus):
Found closer to the lining of the gut to control secretion, absorption of nutrients and blood flow to help digestion
348
Describe the autonomic control of the GIT?
Sympathetic innervation = Spinal nerve T5-L2
Parasympathetic innervation = Vagus nerve for the foregut and midgut and S2-S4 spinal nerves for the hindgut (also called pelvic splanchnic nerves)
349
Describe the sympathetic innervation of the abdominopelvic viscera?
1. Sympathetic nerves start from T5-L2 and travel through splanchnic nerves
2. The splanchnic nerves carry the signals and eventually synapse at special nerve centres called ganglia (i.e. celiac, superior mesenteric, aorticorenal and inferior mesenteric plexuses)
3. After synapsing, the postsynaptic nerves follow blood vessels to reach the intestines where they provide nerve innervation to the foregut, midgut and hindgut
350
List the splanchnic nerves and include their spinal cord level?
Greater splanchnic nerve (T5-T9/10)
Lesser splanchnic nerve (T10-T11)
Least splanchnic nerve (T12)
Lumbar splanchnic nerve (L1-L2)
351
Describe the parasympathetic innervation of the abdominopelvic viscera?
Vagus nerve = Sends parasympathetic signals (via the anterior and posterior vagal trunks) to the foregut and midgut
Pelvic splanchnic nerves = Carry preganglionic parasympathetic fibres from S2-S4 and enter the inferior hypogastric plexus in the pelvis to control the hindgut
352
What does the inferior hypogastric plexus contain?
Sympathetic and parasympathetic nerves which help control pelvic organs like the bladder, rectum and reproductive organs
353
What does the superior hypogastric plexus contain?
Sympathetic nerves from L3 and L4 ganglia
354
What do the left and right hypogastric nerves contain?
Parasympathetic signals from S2-S4 spinal cord (via the pelvic splanchnic nerves)
355
Identify the plexuses of the GIT?
37.Superior hypogastric plexus
16.Left and right hypogastric plexus
21.Inferior hypogastric plexus
356
Explain the parasympathetic innervation of the large intestine?
Vagus nerve = Appendix, caecum, ascending colon and proximal 2/3 of the transverse colon (aka midgut)
Pelvic splanchnic nerves (S2-S4 spinal nerves) = Distal 1/3 of the transverse colon, descending colon, sigmoid colon, rectum and proximal anal canal (aka hindgut)
Pudendal nerve (S2-S4 spinal nerve) = Distal anal canal and anus
357
What is Hirschsprung disease?
A genetic disorder where nerve cells (ganglionic cells) are missing in some parts of the colon
This causes constriction of the distal part and dilation of the proximal part of the colon due to the buildup of food, leading to severe constipation and a swollen belly
358
Why does referred pain occur in the GIT?
Because many different nociceptors (pain sensors) share the same pathway in the spinal cord, which can confuse the brain and lead to pain sensation from visceral organs being perceived on the surface of the body
359
What is a characteristic of visceral pain?
Poor and dull
360
Where is the referred pain in the following areas:
Foregut?
Midgut?
Hindgut?
Foregut = Epigastric region
Midgut = Umbilical region
Hindgut = Pubic region
361
What is unique about the skin and muscles of the anteroabdominal wall?
Somatic pain is sharp and well localised
362
363
Name the planes that separate the abdominal quadrants and identify some of the organs located in each quadrant?
364
Identify the abdominal regions and the planes that separate these regions?
365
Where is the transpyloric plane located and what organs does it go through?
Location = 9th costal cartilage and in line with L1 vertebra
Organs it goes through = Fundus of the gallbladder, hilum of the left and right kidney, first 1/4 of the duodenum, pylorus of the stomach and neck of the pancreas
366
What is the approximate vertebral level of the arteries of the abdominopelvic wall?
Celiac trunk = Upper border of L1
Superior mesenteric artery = Lower border of L1
Renal artery = L2
Inferior mesenteric artery = L3
Bifurcation of aorta = L4
Joining of common iliac veins to form the inferior vena cava = L5
367
Where may there be referred pain if someone presents with appendicitis?
The appendix is a derivative of the midgut and the pain is carried by sympathetic fibres to the T10 level of the spinal cord to the umbilical abdominal region
368
Identify the sites of referred pain for abdominal organs?
369
