The Liver Flashcards
1
Q
The Liver
A
- Site for glucose and Fat metabolism
- Burial ground for RBC
-Bile, Hormone (Angiotensinogen, insulin- like growth factor), Urea Production - Glycogen storage
- Detoxification
2
Q
Pancreas
A
- Exocrine pancreas = Produce digestive enzymes
- Endocrine Pancreas = Produces hormones such as insulin, glycogen
3
Q
Esophagus and Oral Cavity
A
- Secretion = Saliva (salivary glands)
- Digestion = Carbs
- Motility = Chewing and Swallowing
4
Q
Stomach
A
- Secretion = HCL (parietal cells), Pepsinogen and gastric lipase (chief cells), mucus and bicarbonate, Gastrin ( G cells), Histamine (ECL cells)
- Digestion = proteins, Fats ( small amount)
- Absorption = Lipid soluble, alcohol and aspirin
- Motility = peristaltic mixing and propulsion (movement of food)
5
Q
Small Intestine
A
- Secretion = Enzymes ( enterocytes), mucus (goblet cells), Hormones (CCK, secretin, GIP, etc)
- Digestion = polypeptide, carbs, fat, nucleic acid
- Absorption = AA, small peptide, monosaccharides, FA, cholesterol, nitrogenous water base, monoglycerides, ions, water, minerals, vitamins
- Motility = mixing and propulsion primarily by segmentation, some peristalsis
6
Q
Large Intestine
A
- Secretion = Mucus (goblet cells)
- Digestion = None (except by bacterial)
- Absorption = segmental mixing, mass movement for propulsion
7
Q
Mucosa
A
- They contain layers of epithelial cells ( these cells are transporting cells, exocrine and endocrine cells, plus Stem cells)
- They contain CT ( lamina propria), small blood and lymph vessels, nerve fibers and wandering immune cells
- Mucularis mucosae
8
Q
Submucosa
A
- they are CT with lymphatic and Blood vessels
- Contain submucosal plexus
9
Q
Muscularis Externa
A
they contain longitudinal layer of smooth muscles + myenteric plexus
10
Q
Serosa
A
they are circular layer of smooth muscles
11
Q
Smooth Muscle
A
- Non- straited, Dense bodies (contain actin), myosin, cross bridge arrangement, its thick filament is regulated and have low levels of energy (involuntary movement)
- Poorly developed, elongated, single nucleus, spindle shaped cells
- membrane potential -55mv, low excitability, Autonomic nerve fibers
12
Q
Smooth Muscle Communication
A
- Single unit contraction ( contains gap junctions, unisom contractions when stimulated, branched, contain receptors on each cell to accept neurotransmitters, located within the walls of hollow organs e.g bile duct, GI tracts, ureters, uterus and blood vessels
- syncital
13
Q
Smooth Muscle Communications
A
- Multi unit contraction ( no gap junction, each cells contract independently when stimulated, found in the iris and the ciliary of the eye, male reproductive duct, piloerector muscles
14
Q
Smooth Muscle Contraction ( Tonic contraction)
A
- Muscle is always contracting without relaxation phase
- Found in the orad (upper) region of the stomach and in the lower esophageal, ileocecal and internal anal sphincters
15
Q
Smooth Muscle Contraction (Phasic contraction)
A
- Muscle contracts but have time to relax
- Found in esophagus, gastric antrum, small intestine and all tissues involved in mixing and propulsion
16
Q
Electrical Activity of smooth muscle (slow wave potential)
A
- Slow wave potential ( Normal resting potential of the GI smooth muscle)
- They are generated without simulation
- when acted upon by Excitatory agents ( Ca2+) at the moment when it is close to its threshold, it will fire AP and contracts
- Interstitial cells pf cajal ( ICC) located in the myenteric plexus
17
Q
Fate of Ca2+ in Smooth Muscle
A
Ca comes in - Binds with Calmodulin (CAM) to form a complex - The complex will bind with Myosin light chain Kinases (MLCK), the MLCK complex will be phosphorated - Contraction occur
18
Q
Motility of Smooth Muscle
A
- Electrical activity (AP) always precedes mechanical activities ( Contractions)
- Contraction will aid grind, mix and fragment food so they can be digested and absorbed + they propel food towards aboral direction
-
19
Q
ACh
A
- Cholinergic
- Cause contraction of sphincters
- Increase salivary secretion
- Increase secretion
- pancreatic secretion
20
Q
NE
A
- Adrenergic
- Relaxes the sphincters
- Increases Salivary secretion
21
Q
Vasoactive Intestinal Peptide (VIP)
A
- Gotten from the neurons of the enteric NS
- Relaxes the smooth muscle
- Increase intestinal secretion
- Increases Pancreatic secretion
22
Q
Nitric Oxide -
A
- Triggers relaxation of smooth muscle cells
23
Q
Gastrin- Releasing Peptide ( GRP) also known as Bombesin
A
- Increase Gastrin secretion
24
Q
Opiates ( Enkephalins)
A
- Decreases intestinal secretion
25
Neuropeptide Y
- Decreases intestinal secretion
26
Substance P
Increases salivary secretion
27
Smooth Muscle Reflexes ( Long Reflex)
Send signal to the CNS from the receptor inside and outside of the GI tract
28
Smooth Muscle Reflexes ( Short Reflex)
- The stimulus is sensed by the receptors within the GI tract and the information is entirely process in the enteric NS
- They occur in the GI without communicating with the CNS
29
Gastrin
- ECL and parietal cells
- Stimulate gastric acid secretion and mucosal growth
- Will be inhibited by Somatostatin
30
Cholecytokinin (CCK) or I cells
- Target is gallbladder, pancreas and stomach
- I cells
- Stimulate gallbladder contraction and pancreatic enzyme secretion
- Stop gastric emptying and acid secretion
- Promote satiety ( help us feel full)
- Can act as neurotransmitter
31
Secretin ( S cells)
- Target is pancreas and stomach
- They stimulate bicarbonate secretion
- inhibit gastric emptying and acid secretion
32
Motilin ( endo M cells)
- Works in gastric and intestinal smooth muscle
- They stimulate the migrating motor complex
- They will be inhibited by eating a meal
33
Gastric Inhibitory Peptide ( GIP) also known as K cells (Glucose dependent insulinotropic peptide
- Works on the beta cells of the pancreas
- They stimulate insulin release ( a feed forward mechanism)
- They inhibit gastric emptying and acid secretion
34
Glucagon Like Peptide -1 ( GLP-1) Also known as L cells
- Works on the endocrine pancreas
- They help stimulate insulin release
- They inhibit glucagon release and gastric function
- They help promote satiety
35
Ghrelin
- Makes Me hungry ( Increase appetite)
- Pancreas and Adrenal ( Gastric mucosal cells during fasting state)
- Hypothalamus
- Stimulate orexigenic neuron and inhibit anorexigenic neurons
- Loss of activity = obesity as Leptin is inhibited so Pt. keeps eating nonstop
36
Leptin
- Makes me full ( decrease appetite)
- Increase energy expenditure
- Works on the fat cells ( adipose tissues)
- Hypothalamus
- Stimulate anorexigenic neurons and inhibit orexigenic neurons
37
Incretins
GLP-1 and GIP
38
Amylins
- Similar to Incretins except they don't promote insulin secretion
- They prevent big spike that occurs when eating
- They slow down gastric emptying and decrease plasma glucose thus glycemic control
39
Oral cavity
- Entry point for food before digestion in the stomach and intestine occur
- Extent of the oral cavity = Lips to oropharyngeal isthmus
- Boundaries = Oral vestibule ( Upper lips innervation will be CN V2, Lower lips will CN V3),
- Lymph drainage = upper lip & lateral lower lips (Submandibular)
40
Ascending Palatine Artery
Fascial Artery
41
Venous Drainage of Palate
Branches of maxillary artery and tributaries of pterygoid venous plexus
42
Sensory Innervation of Palate
CN V2
43
Motor innervation of palate
All muscle of the soft palate is supplied by CN X except for tensor veli palatini supplied by CN V3
44
Muscle of the tongue (Extrinsic)
Helps in movement of the tongue
45
Muscle of the tongue (Intrinsic)
Helps the shape of the tongue
46
Genioglossus (Extrinsic tongue muscle)
Helps in wagging of the tongue to the contralateral side
47
Hyoglossus (Extrinsic tongue muscle)
Helps depresses tongue by pulling it side by side + shortens tongue (retrude)
48
Styloglossus ( Extrinsic tongue muscle)
- Elevate and curls tongue sides
- Work with genioglossus to form a central trough during swallowing
49
Palatoglossus ( Extrinsic tongue muscle)
- Big boss innervated by pharyngeal plexus (CN X)
- Elevate posterior tongue ( depresses soft palate)
- Constrict the isthmus of fauces (L. the throat)
50
Superior Longitudinal (Intrinsic tongue muscle)
- Curls tongue upward
- Elevate apex and side of tongue
- Shorten tongue
51
Inferior Longitudinal ( Intrinsic tongue muscle)
- Curls tongue downward
- depresses apex of tongue
- shortens tongue
52
Transverse ( Intrinsic tongue muscle)
narrows and elongate (protrude) tongue
53
Vertical ( intrinsic tongue muscle)
flattens and broadens the tongue
54
Motor innervation of tongue
all muscle of the tongue is supplied by Hypoglossal Nerve (CN XII) except palatoglossus muscle supplied by pharyngeal plexus ( CN X)
55
Sensory innervation of tongue (Anterior 2/3rd)
- Lingual Nerve ( CN V3) = general sensation
- Chorda tympani Nerve (CN VII branch) = Taste sensation
56
Sensory innervation of tongue ( Posterior 1/3rd)
- CN IX = both general and taste sensation
57
Sensory innervation of tongue (small area in front of the epiglottis)
- Internal Laryngeal nerve = CN X
58
Injury to tongue ( clinical correlates)
- Injury to Hypoglossal Nerve ( CN XII) = tongue deviate to the paralyzed side during protrusion because of the action of the unaffected genioglossus on the other side
- Injury to the Pharyngeal plexus, the soft palate (uvula) deviates to the opposite side due to unopposed action of opposite side muscle
59
Lymph drainage of tongue (posterior 1/3rd)
Superior deep nodes on both sides
60
lymph drainage of the tongue ( medial part of anterior 2/3rd)
Inferior deep cervical nodes
61
lymph drainage of tongue ( lateral part of anterior 2/3rd)
Submandibular nodes
62
lymph drainage of tongue ( Apex and frenulum)
Submental nodes
63
Lymph drainage of tongue ( Posterior 1/3rd area near midline groove)
Drains bilaterally
64
Salivary Glands ( secretes saliva)
- Parotid glands
- Submandibular glands
- Sublingual glands
65
Salivary glands
- Lubricates food during mastication
- Keep the mucus membrane of mouth moist
- Begins digestion by secreting Amylase to aid digestion of food bolus
- Serves as intrinsic mouth wash
- Help prevent tooth decay and give us the ability to taste
66
Parotid gland
- Located between mandible, styloid process and mastoid process
- Parotid sheath ( capsule)
- Have a duct to transport its secretion
67
Parotid gland structures
- Fascial nerve
- Retromandibular veins
- External carotid artery
68
Submandibular glands
- Lies along the body of the mandible
- secretion = Mixed
69
Sublingual glands
- Lies in the floor of the mouth between the mandible and genioglossus muscle
- Secretion = Mucus
70
Clinical Correlates of the parotid gland
- Mumps = Inflammation of the parotid ( parotiditis) + Pt. present with pain due to stretch of the fascia covering the gland.
- Parotidectomy can be used to relief the pain, just be careful to preserve the facial nerve during procedure as parotid plexus (CNVII (7)) is embedded within the gland
- Testing = CT or MRI
71
Pharynx
- Extent = Base of base of cranium to cricod cartilage (C6)
- Nasopharynx = behind nose + above palate
- Oropharynx = Behind mouth
- Laryngopharynx = Behind larynx
72
Pharynx (Oropharynx)
- Digestive function
- Palatine tonsils
- Boundaries = Soft palate, base of tongue, palatoglossal and palatopharyngeal arches
73
Tongue
- Anterior 2/3rd = 2nd pharyngeal arch
- Posterior 1/3 = 2,3 4 arches
74
Pharynx ( Laryngopharynx/ Hypopharynx)
- Continuous with esophagus
- Communicate anteriorly with larynx
- Extent = Tip of epiglottis to cricoid cartilage
- Nerve supply = internal and recurrent laryngeal nerve
75
Pharynx Constrictor muscle ( Superior Pharyngeal)
- External pharynx muscle
- Vagus (CN X) nerve that constrict the wall of pharynx during swallowing
76
Pharynx Constrictor Muscle (Middle Pharyngeal)
- External pharynx muscle
- Vagus (CN X) nerve that constrict the wall of pharynx during swallowing
77
Pharynx constrictor muscle ( Inferior pharyngeal)
- External pharynx muscle
- Vagus ( CN X) nerve that constrict the wall of pharynx during swallowing
78
Pharynx Internal Muscle layer ( Palatopharyngeus)
- Vagus nerve ( CN X)
- Elevate ( shorten and widens) the pharynx and larynx during swallowing and speaking
79
Pharynx internal muscle layer ( salpingopharyngeus)
- Vagus nerve (CN X)
- Elevates ( shorten and widens) the pharynx and larynx during swallowing and speaking
80
Pharynx internal muscle layer ( stylopharyngeus)
- Glossopharyneal nerve (CN IX)
- Elevate ( shortens and widens) the pharynx and larynx during swallowing and speaking
81
Nerve supply of the pharynx (sensory)
- Derived from the pharyngeal plexus in the posterior wall of pharynx
- CN IX ( Glossopharyngeal) nerve
- Anterior and superior nasopharynx CN V2
82
Nerve supply of the pharynx ( motor)
- Vagus (CN X) supplies all the muscle except stylopharyngeus muscle CN IX (9)
83
Clinical correlate of pharynx
- Pharyngeal tonsilar ring of waldeyer = consist lingual tonsil, palatine tonsil, tubal tonsils and pharyngeal tonsils
- During Tonsilectomy, bleeding may occur from injury to external palatine vein that will drain into the facial vein
84
Pharynx arterial supply
- Facial nerve = Tonsilar artery and ascending palatine
85
Pharynx arterial supply
- Maxillary artery = Descending palatine
86
Pharynx arterial supply
- External carotid artery = Lingual and ascending pharyngeal arteries
87
Esophagus
- Lies behind the trachea
- Left atrium of the heart is located in front of the esophagus in the lower part of the mediastinum
- Passes through the diaphragm at T10 vertebra
- Terminates at esophagogastric junction by entering the cardiac orifice of the stomach
88
Esophagus structure
- Upper 1/3rd = skeletal muscle = voluntary movement
- Middle 1/3rd = both skeletal and smooth muscle
- Lower 1/3rd = Smooth muscle = involuntary = purely autonomic sensation
89
Esophagus ( Parts)
- Cervical = midline between trachea and cervical vertebra, left side (thoracic duct)
- Thoracic = lies between mediastinum ( space between two pleural cavities)
- Abdominal
90
Clinical Correlates ( Esophagus)
- Enlargement of the left atrium will manifest as dysphagia
- Tracheo - esophageal fistula (TEF) = common birth defect, failure of the esophagus and trachea partitioning wheere esophagus ends in blind pouch and lower part communicate with the trachea
- Esophageal Cancer = most common ( Pt. present with dysphagia), this is a compression of the recurrent laryngeal nerve thus producing HOARNESS of Voice
- Portosystemic shunt = Lower end of esophagus is a common site, the abdominal part will drain into the portal venous system. The Thoracic part drains into the systemic venous circulation and when dilated, these veins can form ESOPHAGEAL VARICES
91
Esophagus ( Cervical Constrictors) / Pharyngoesophargeal sphincter
- Upper esophageal sphincter
- 15cm from incisor teeth
92
Esophagus ( Thoracic constrictors - Broncho- aortic)
- Crossing of aorta
- Crosses the left main bronchus
93
Esophagus ( Diaphragmatic) constrictor
- Passes through the esophageal hiatus of the diaphragm
- Please be aware of this boundaries during endoscopy
94
Oral Cavity
- Lips, cheeks, teeth, gums (gingivae), tongue, uvula and palate
95
Oral Mucosa ( cell types)
- Masticatory = gingiva and hard palate = stratified squamous keratinized/ parakeratinized epithelium
- Specialized = dorsal surface of the tongue = contain Lingual papillae
- Lining of the remaining part of the oral cavity = stratified squamous non keratinized epithelium
96
Lips
- Cutaneous region = hair follicles, sebaceous and sweat glands
- Vermilion or red region ( no glands) = gets cracked in cold weather
- Oral mucosa region = wet surface and mucous salivary glands = Vestibular aspect
97
Tongue Histology and structure
- Anterior 2/3rd = Skeletal muscle (longitudinal, transverse and oblique)
- Posterior 1/3rd = Posterior to terminal sulcus) Lingual tonsils = Aggregation of lymphocytes
98
Lingual papillae of tongue (Filiform)
- Dorsal surface anterior to the sulcus terminalis
- Specialized mucosa
- Most numerous, conical in shape
- NO TASTE BUDS
- stratified keratinized squamous epithelium
99
Lingual papillae of tongue (Fungiform)
- Dorsal surface of the tongue anterior to the sulcus terminalis
- Most numerous at the tip of the tongue
- Mushroom shaped
- FEW TASTE BUDS
- Stratified non-keratinized squamous epithelium
-
100
Lingual papillae of tongue ( Foliate)
- Dorsal surface of the tongue posterolateral aspect of the anterior 2/3rd of the tongue
- Have taste buds for the first 2 years of life that later degenerate
- Gland of Von Ebner release their secretion into the furrows
101
Lingual papillae of tongue ( Circumvallate )
- Anterior to the sulcus terminalis
- NUMEROUS TASTE BUDS
- Surrounded by a deep, moat like furrow
- Glands of Von Ebner to release their serous secretion into the bottom of the moat- like - depression
102
Taste buds
- Oval, pale stained on H/E stain
- Have a small opening onto the epitheliums called the TASTE PORE
-Gustatory cells microvilli (sensory cells)
- Supporting cells
- Basal cells ( Stem Cells)
103
Salivary glands (Acini) Types
- Salivon
- Acini
104
Salivary glands ( Acini - Salivon)
- Basic secretory
-consist of Acinus, intercalated duct and excretory duct
105
Salivary glands ( Acini)
- Tubular and spherical
- Myoepithelial at the base
- Serous cells (protein - secreting)
- Mucous cells (mucin - secreting)
- Mixed ( Both serous and mucous)
106
Salivary duct ( Intercalated duct )
- Receive secretion from acinus
- Lined by simple cuboidal epithelium + merge into Striated duct (contain mitochondria) and excretory duct (cuboidal/ columnar epithelial)
- CT
107
Salivary gland ( Parotid glands)
- Serous acini only
- Watery consistency (20%)
- Adipose tissue
108
Salivary glands ( Submandibular)
- Serous
- Moderately viscous ( 70%) = most salivary production
- Mixed/ mucous acini (S:M = 4:1)
- Demilunes
- Striated ducts
109
Salivary glands ( Sublingual)
- Elongated mucous acini
- Mixed secretion (S:M = 1:4)
- Viscous ( very thick and 5%)
- Demilunes
110
GI tract Layers
- Mucosa
- Submucosa
- Muscularis propria
- Serosa or adventitia
111
GI Track layers ( Mucosa)
- Epithelial lining = stratified squamous ( Mouth, upper esophagus, anus) and simple columnar ( stomach to rectum)
- Lamina propria = LCT, BV, Smooth muscle cells and small glands
- Muscularis mucosae ( Thin layer of Smooth muscle cells) that allow for movement
112
GI tract layers ( Submucosa)
- Large blood vessel + lymph vessels
- Submucosal (meissner) plexus = sensory ( autonomic nerves)
- Contain Mucous gland
113
GI tract (Musculosa/ Muscularis external)
- Two layer of smooth muscle
- Inner layer ( close to the lumen) = circular fibers
- External layer = Longitudinal fibers
- CT = contain BV, lymph vessels, Myenteric (Auerbach nerve plexus
- Contraction of this layer which mix and propel the luminal content forward with the aid of the myenteric plexus
114
GI tract ( Serosa/ Adventitia)
- External Muscular layer
- Adventitia = sheet LCT, BV, Lymph vessels, Adipose tissue + close to the outside
- Serosa ( Simple squamous epithelium) = Mesothelium
115
Clinical correlate of the GI tract
- Hirschsprung Disease (Enlarge colon) = Plexus in the digestive tract are absent or severely injured
116
Esophagus Histology layer
- Mucosa
- Submucosa
- Muscularis externa (Muscular layer)
- Adventitial
117
Esophagus Mucosa
- Non keratinized stratified squamous epithelium
- Close to the Lumen
118
Esophagus Submucosa
- Mucus secreting glands ( Esophageal glands) to lubricate and protect the mucosa
119
Esophageal Muscularis Externa
- Inner circular layer and outer longitudinal
- Upper 1/3rd skeletal muscle ( striated)
- Middle 1/3rd Mixed ( smooth/ skeletal)
- Lower 1/3rd Smooth muscle
120
Esophageal Adventitia
- Forms outer layer except within abdominal cavity where it is SEROSA
121
Esophagogastric junction Histology
- Non-keratinized stratified squamous epithelium that can change to simple columnar epithelium of the gastric mucosa (Metaplasia)
122
Esophageal Cardiac gland
- Secrete additional neutral mucus to protect the esophagus from gastric contents
123
Saliva functional unit
Salivon
124
Function of Saliva (alpha - amylase)
- Ptyalin = helps break down starch and inactivated at a pH less than 4
125
Function of Saliva (Mucin)
- Lubricate food
- Assist in mastication
- Facilitate deglutition
- Help us in speech by helping us move our lips and tongue
- Protect oral mucosa by secreting mucous to neutralize acid
126
Function of Saliva ( lingual lipase)
- They help us digest fat so they are abundant in the stomach
127
Function of Saliva ( Lysozymes)
- They have the same function as a lysozyme (macrophages)
- Bractericidal ( used for macrophages)
128
Function of Saliva ( IgA)
- Local Immunity
129
Function of Saliva ( Lactoferrin)
- Binds irons and Arrest bacteria
- Multiplication. and dental caries (bacteriostatic - stunt bacterial growth)
- Keep the mouth moist
- Serve as solvent for molecules that stimulate the taste buds
- They serve as vehicle for excretion of heavy metals (lead), viruses ( polio, rabies), and drugs
130
Function of Saliva ( Proline rich protein)
- They help bind to toxic tannin
- They maintain the oral pH
131
Function of Saliva ( Nerve growth factor)
- Growth of sympathetic ganglia
- They help regulate water balance
- They help maintain the middle ear pressure adjustment
- In animal they help regulate temperature
132
Saliva Composition
- Organic Component ( 1%) = Ptyalin, mucin, lysozyme etc.
- Water ( 98.5%)
- Inorganic component (0.5%)
133
Saliva
- Volume ( 800 - 1500ml/day)
- pH ( slightly less than 7 and while with active secretion, it will be 8)
- Specific gravity = 1002 - 1012
134
Inorganic Constituents of Saliva (Anions) -
- Chloride
- Bicarbonate
- Phosphate
- Halides ( iodine and fluorine)
135
Inorganic Constituents of Saliva (Cations) - Ions vary in amount according to the flow
- Na
- K
- Ca
- Mg
136
Things that Affect inorganic components
- Stimulus and rate of salivary flow
137
Properties of Salivary Secretion
- Large Volume related
- Low osmolality
- High Potassium Concentration
- Specific organic material
138
Salivary Secretion ( Primary)
- Acinar cells
- Isotonic to plasma (ECF)
- Secrete Ptyalin, mucus and ions
139
Salivary Secretion ( Secondary- Modification by duct)
- Duct system
- Rate of flow
- Hypotonic to plasma
140
Rate of Secretion ( Secondary secretion)
- Increased = less modification by duct + resemble plasma
- Decreased = concentrated
- At rest there is increase of K and less Na, Cl and Iodine
141
Acinar (Primary Secretion)
- Basolateral membrane (Na-K pump, Na- K- 2CL symporter
- Apical Membrane ( Cl, and HCO3 anion channel, Na and water moves paracellularly)
142
Secondary modification ( modification by duct cells)
- Na- K pump
- Apical Membrane ( Na and Cl reabsorption, K and HCO3 secretion and Aldosterone
143
Regulation of Secretion ( NS)
- Parasympathetic = ACh = Muscarinic = Ca = Fluid secretion will be greater than protein secretion
- Parasympathetic = NE = alpha- adrenergic = Ca = Fluid secretion will be greater than protein secretion
- Parasympathetic = Tachykinin (NK1) = Ca = Fluid secretion will be greater than protein secretion
- Sympathetic = NE = Beta- Adrenergic = cAMP = Protein secretion will be greater than fluid secretion
144
Chewing and Mastication
- Food will be cut down to bit size and grind
- Surface area will increase for food particles
- Salivary secretion will be increased
- oral cavity will be lubricated to aid swallowing and the chewed food will be mixed with saliva
145
Swallowing / Deglutition (swallowing)
- Food travels to the stomach
- Skeletal ( voluntary) = involuntary/ reflex process
146
Phases of Swallowing (Oral - Stage I)
- Bolus travels from mouth to the esophagus with tons of events
- Voluntary = skeletal muscle
- Chewing - tongue contracts - mouth close and voluntary contraction
147
Deglutition Reflex
- Stimulus = Food in the mouth
- Receptor = touch receptor
- Afferent ( CNS) = CN V, CN IX, CN X
- Centre = Deglutition center, medulla and lower pons
- Efferent = CN V, CN IX, CN X , CN XII
- Effector organ = Pharyngeal muscles
- Response = Involuntary stage of swallowing
148
Phase of Swallowing (Pharyngeal - Stage II )
- Bolus travel from through the pharynx and upper esophagus
- Involuntary = soft palate is elevated as well as nasal cavity = larynx rises = breathing is slightly inhibited = deglutition apnea and epiglottis closes the laryngeal opening
- Mixed ( Skeletal and smooth muscle cells)
149
Phases of Swallowing ( Esophageal - Stage III)
- Pressure is lower than in the pharynx and stomach
- Sphincter is used to control movement of bolus thus creating a barrier
- Peristalisis is transported ( primary and secondary)
150
Esophageal Sphincters
- Upper Esophageal Sphincter (UES)
- Lower Esophageal Sphincter (LES)
151
Esophageal Sphincter (UES)
- INCREASE MUSCLE TONE
- Separate the Pharynx and the upper part of the esophageal
- Skeletal Muscle + Have high muscle tones
- Will constrict to prevent air from entering the stop but can move to allow bolus enter the stomach
- Relax during swallowing while the glottis is closed, reflex is closed and this happens naturally
152
Esophageal Sphincter ( LES)
- Prevent reflux of gastric content into the esophagus
- Remains tonically contracted
- Maintains a resting tone ( slow wave tone)
- Coordinate movement of ingested food to the stomach from esophagus after swallowing
153
Esophageal Sphincter (LES) cholinergic regulation
- Basal tone = Vagal ACh fibers
- Gastrin increase = Increase tone
- Secretin decreases = Relaxation
154
Esophageal Sphincter (LES) Relaxation
- Innervated by Vagus nerve mediated by VIP and NO
- Deglutition or distention of esophagus
155
Peristalsis ( contraction that moves food through the digestive tract)
- Reflex will respond to stretch
- Movement will be from GI tract - Esophagus - rectum
156
Peristalsis Mechanism
- Propulsive Segment ( behind bolus (stimulus (food) , circular contract, longitudinal muscle relax)
- Receiving segment ( In front of bolus, receives bolus, circular muscle relax, longitudinal muscles contracts)
157
Esophageal Peristalsis
- Triggered by local stimulation
- Lumen will obliterate during contraction
- Its strength is proportion to the size of the bolus
- Can be affected by gravity, liquid and solid
158
Peristalsis ( Neurotransmitters)
- They control retrograde direction ( by releasing substance P and ACh, Help contract the smooth muscle cells and push down food)
-They control the anterograde direction ( by releasing VIP and NO) with which they use to relax the circular smooth muscle cell
159
Factors that influence peristalsis
- Intrinsic and extrinsic factors
- Autonomic Nervous System (ANS) to influence transmission
- Parasympathetic stimulation = Helps stimulate peristalsis = NE
- Sympathetic stimulation = Inhibits peristalsis = ACh
- Genesis independent of ANS
160
Esophageal Peristalsis
- Primary = deglutition reflex - bolus enters - at the esophageal ( constriction initiated) - swallowing is initiated- VAGAL FIBER
- Secondary = food remain after primary peristalsis - mechanoreceptors is trigger after activated by food - INTRINSIC NERVE
161
Esophageal Pressure
- Both UES and LES are closed between swallowing and the body is flaccid
- UES pressure is 60mmHG and LES is between 20-40mmHG
- In the thorax, the body pressure is similar to the thorax and sub- atmospheric pressure will vary with respiration
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Modulator of LES pressure ( Hormones)
- Increase Pressure ( Gastrin, motilin, substance P)
- Decreases Pressure ( Secritin, Choleccystokinin (CCK), somatostatin, vasoactive Intestinal Peptide (VIP) Progesterone)
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Modulator of LES pressure (Neutral agents)
- Increase pressure ( alpha- adrenergic agonist, Beta- adrenergic antagonist, cholinergic agonist)
- Decrease pressure ( beta- adrenergic agonist, alpha- adrenergic antagonist, anticholinergic agents)
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Modulator of LES pressure ( Food)
- Increase Pressure ( protein meals)
- Decreases Pressure ( fats, chocolate, peppermint)
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Modulator of LES pressure ( others)
- Increase Pressure ( Histamine and antacid)
- Decrease Pressure ( Theophylline, Prostaglandins E2, E1)
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Clinical Correlates (esophageal disorders)
- Esophageal Achalasia ( Pt. will present with difficulty to have food travel to the LES due to lower esophageal sphincter tone - Buzzwords difficulty of food to go down into the stomach, heartburn) this is due to defective inhibitory pathways of the esophageal enteric NS
- Reflux Esophagitis (Pt. will present with inappropriate LES relaxation, due to decrease muscle tone)
- Gastroesophageal Reflux Disorders (GERD) = Pt. will present with normal LES tonically contracted, acidic content of the stomach to reflux back into the distal part of the esophagus, presentation will also be opposite to ACHALASIA, increase stomach volume or pressure or increase acid production. if this reflux continue, the mucosa can be damaged thus pt. will have constant heartburn and indigestion
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The Scarpa Fascia
- Continue to the perinium as the Colles fascia
- Fuses with perineal membrane
- Urine from rupture urethra can accumulate in the anterior abdominal wall between the scarpa fascia and the anterior rectus shealth and it spreads superior
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Muscle of Anterolateral abdominal wall
- Five bilaterally paired muscles
- Flat Muscles
- Longitudinal Muscles
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Muscles of Anterolateral abdominal wall ( Flat muscle) - innervated by thoracoabdominal nerves
- External oblique ( EO) -T7-T11
- Internal oblique (IO) - (T7 - T11, and 10th - 12th ribs)
- Transverse abdominis (TA) - T7 - T12
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Muscle of anterolateral abdominal wall ( Longitudinal Muscle) - innervated by thoraco-abdominal and subcostal nerves
- Rectus Abdominis (RA)
- Pyramidalis ( sometimes absent in 20% of the population and it's a content of the rectus sheath
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Superficial layers ( Anterolateral abdominal wall layers)
- Superficial fatty layer ( Camper's fascia)
- Deep membranous layer (Scarpas' fascia)
- continues into the perineum as colles's fascia and forms dartos muscle in scrotum
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External abdominal oblique and aponeurosis
Forms inguinal ligament, superficial inguinal ring and external spermatic fascia
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Internal abdominal oblique and aponeurosis
- Joins with transversus abdominis to form conjoint tendons
- Forms cremaster fascia and muscle
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Transverse Fascia
- Forms the deep inguinalring and the internal spermatic fascia
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Arcuate Line
- This is a transition between the posterior rectus sheath that will cover the superior 3/4 of rectus abdominal proximally and transversalis fascia covering inferior 1/4
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Content of the Rectus Sheath
- Muscle = Rectus abdominis and pyramidalis
- Vessels = Superior and inferior epigastric arteries, veins and lymphatics
- Nerves = T7 - T12 nerves
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Functions of anterolateral abdominal muscles
- Strong support for the abdominal cavity
- Protect abdominal viscera from injury
- Produce force required for defecation, micturition, vomiting and parturition
- help flex Nd rotate the trunk to help us maintain posture
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Commonly used Abdominal incision
median, Paramedian, transverse, suprapubic, subcostal, and gridiron
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Incisional Hernia
- Protrusion of omentum/organ through a surgical incision/scar
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Six common cause for abdominal distension
- Food, Fluid, Fats, Faces, Flatus and Fetus
