Post on 07-Nov-2014
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Gastrointestinal SystemAnatomy
By
Dr. THAAER MOHAMMED DAHER ALSAAD
M.B.Ch.B.(MBBS) F.I.B.M.S.(Ph.D.)
SPECIALIST IN GENERAL SURGERY
SENIOR LECTURER
IMS MSU
Highlights
• Mouth
• Esophagus
• Stomach
• Small intestine
• Large intestine
• Rectum and Anal canal
• Liver, Pancreas, Salivary glands
Mouth or Oral Cavity
• lies below the nasal cavity.
• It has floor and roof ,and lateral walls,
• it open to the face through the oral fissure, and is continuous with the cavity of the pharynx to form the oropharynx( the oral part of the pharynx).
Mouth or Oral Cavity
Function of the oral cavity
1-it is the inlet for the digestive system involved with the initial processing of food, which is aided by secretions of the salivary gland.
2- it manipulates sounds produced by larynx and one out come of this is speech.
3-it can be used for breathing because it open in the pharynx, which a common pathway for food and air.
The Teeth
Alligators are known for their large mouths and sharp teeth.
Illustration of the inside of a human mouth
A closed human mouth
cavitas oris
Models of human teeth as they exist within the alveolar bone
Histologic slide of tooth erupting into the mouth.
A: ToothB: Gingiva
C: BoneD: Periodontal ligaments
Radiograph of lowerdifferent stages right third, second, and first molars in of development
Deciduous teethFront Teeth:
A. Central incisorB. Lateral incisorC. Canine or eye tooth
Back Teeth:D. First molarE. Second molar
Permanent teeth
Front Teeth:
1. Central incisor2. Lateral incisor3. Canine or eye tooth
Back Teeth:
4. First premolar5. Second premolar6. First Molar7. Second Molar8. Third Molar Or Wisdom Tooth
The Teeth
• I, C, P, and M (incisors, canines, premolars, and molars).
• The permanent or adult dental formula of humans is I (2/2, C 1/1, P 2/2, M 3/3) x2= 32.
• The dental formula for humans following the format for would be;
• 2:1:2:3/2:1:2:3,• where the numbers correspond to• I:C:P:M (upper)/I:C:P:M (lower).
• Deciduous teeth
• Central incisor 6 month
• Lateral incisor +2 8 month
• First molar +4 12 month
• Canine +4 16 month
• Second molar +4 20 months
The 1st deciduous molar appears before the canine.
The Teeth
• Permanent teeth• First molar 6 years• Central incisor +1 7 years• Lateral incisor +1 8 years• Canine +1 9 years• Premolar +1 10 years• Second molar +1 11 years• Third molar ------------------ 17 years +• 3rd molar = wisdom tooth, it is no infrequently
one or more 3rd molars may fail to erupt.
The Teeth
Differences in Structure of Different Teeth• The teeth are arranged in arch,
• Terms like anterior, posterior, medial and lateral are confusing.
• Buccal (labial) surface =
• the surface of the tooth facing the lip or cheek.
• Lingual (or palatal) surface =
• the surface of the tooth facing towards the tongue.
• Mesial surface =
• the surface of the tooth nearest the middle line.
• Distal surface =
• the surface of the tooth opposite to the mesial surface.
• Occlusal surface =
• the upper surfaces of the lower teeth and the lower surfaces of the upper teeth.
• Occlusal surface of the incisor teeth forms a sharp cutting edge.
• In the canine it is pointed.
• In the premolars and molars the occlusal surface bears rounded elevations or cusps.
• In fact all lower teeth lie slightly anterior (and mesial)
• To their upper counterpart.
Differences in Structure of Different Teeth
Blood and Nerve Supply to the Teeth
• The lower teeth
• are supplied by branches from the inferior alveolar artery (branch of maxillary artery); and by
• the inferior alveolar nerve (branch of mandibular nerve).
• The upper teeth• Are supplied by the anterior and posterior superior alveolar
branches of the maxillary artery, and by the
• Anterior, middle and posterior superior alveolar nerves (branches of the maxillary nerve and infraorbital continuation).
The Tongue
. Tongue--Musculature
Genioglossus –
depresses the tongue; posterior part protrudes tongue.
Hyoglossus –depresses and retracts the tongue. Styolglossus –retracts tongue and draws its edges up to create a trough for swallowing. Palatoglossus –
elevates the posterior part of tongue. Intrinsic muscles of tongue –
are confined to the tongue and do not attach to bone.(SLM =superior longitudinal muscle, ILM = inferior longitudinal muscle,
transverse muscle fibers, vertical muscle fibers)-
Vascular supply The lingual artery, a branch of the external carotid artery is the major arterial blood supply to the tongue .
Tongue innervation.
The posterior one-third of the tongue receives both generalsensory and special sensory from CN IX innervation.
A small posterior region of the tongue receives sensory innervation from CN X.The tongue receives general sensory innervation from the lingual branch of CN V for the anterior two-thirds,and special sensory (taste) from the chorda tympani nerve, a branch of CN VII.
Motor innervation from CN XII.
The Palate• Soft palate and hard palate
• Soft palate muscles:
1. Tensor palati
2. Levator palati
3. Musculus uvelae
4. Palatopharyngeus
• Action of palatine muscle: the muscle are responsible for the movement of the palate with deglutition and with speech.
• The levator palate helps to close the pharyngeal isthmus by elevating the palate and bringing it in contact with the posterior wall of the pharynx.
• Nerve supply
• All muscles oa the palate, except tensor palati, are supplied by the cranial part of the accessory nerve through the pharyngeal branch of the vagus.
• The tensor palati is supplied by the mandibular nerve.
The Palate
Anatomy of The pharynx
Site
Midline of the neckFrom skull base to esophagusIn front of upper 6 Cervical vertebra
Behind :The Nose
The MouthThe larynx
Seen from behind
Anatomy of The pharynx
Shape
Irregular Fibromuscular tube lined by mucous membrane
Length: 15 cm
Anatomy of The pharynx
Structure
The wall is formed of 4 layers
1-Mucous membrane
2- pharyngeal aponeurosis
3-muscle layer
4-Bucco-pharyngeal fascia
Stratified squamous epithelium except the nasopharynx, it is pseudo-stratified with goblet cells
Loose connective tissue which contains lymphoid tissue that aggregates in some areas forming tonsils (Waldayer’s ring) Formed of 3 muscles, superior middle and inferior constrictor muscles
A thin coat of connective tissue
• Three constrictors:
• Superior constrictor
• Middle constrictor
• Inferior constrictor; consist of two part:
1. Thyropharyngeus
2. Cricopharyngeus
Pharyngeal muscles
Pharyngeal muscles
• In addition to the constrictors, the pharynx has three muscles the fibers of which run longitudinally.
• These are the:1. Stylopharyngeus
2. Palatopharyngeus
3. salpingopharyngeus
What is Waldeyer’s ring?
The lymphoid tissue in the
pharyngeal aponeurosis
aggregates in some areas
forming tonsils:
1-one nasopharyngeal tonsil
2- two palatine tonsils
3- two lingual tonsils
Anatomy of the pharynxCompartments
• Nasopharynx
• Oropharynx
• Laryngopharynx
(Hypopharynx)
Seen from behind
• Nasopharynx
• Oropharynx
• Laryngopharynx
(Hypopharynx)
Seen from lateral
Nasopharynx
-Behind the nasal cavity
-Extends from skull
Base superiorly to the
soft palate inferiorly
- Communicates inferiorly with the oropharynx through the velo-pharyngeal sphincter
- The nasopharyngeal tonsil lies in the roof
- The pharyngeal opening of ET lies in the lateral wall
Oropharynx
Behind the oral cavity (in front of 2nd&3rd
Cervical vertebra)
From the soft palate superiorly to tip of epiglottis inferiorly
Communicates:
Anteriorly with the oral cavity
Superiorly with the nasopharynx
Inferiorly with the hypopharynx
The palatine tonsils lie laterally
between the anterior and posterior
pilars
The tonsils lie between the Two pillars
Hypopharynx
Behind the Larynx (in front of 3rd to
6th Cervical vertebra)
From the tip of epiglottis superiorly to
the lower border of cricoid cartilage
Inferiorly
Communicates:
- Anteriorly with the Larynx
- Superiorly with the oropharynx
- Inferiorly with the esophagus
The hypopharynx does not only
lie behind the larynx BUT also
Projects laterally on each side of the larynx
So it is formed of :
- Postcricoid region ( behind the larynx)
- Two pyriform fossa (on each side of the larynx
Seen from behind
Cross section
Blood supply
From the External Carotid Artery & its branches
1- Tonsillar artery (from Facial Artery)
2-Ascending palatine artery (from Facial Artery)
3-Ascending pharyngeal Artery (from external carotid)
4-Descending palatine artery ( from Maxillary artery.
5-Dorsalis lingulae artery (from Lingual artery)
Nerve Supply
Motor ---► X Except :
Stylopharyngeus --►IX
Tensor palati --►V
Sensory --►
- Nasopharynx: V
- Oropharynx: IX
- Laryngopharynx: X
Autonomic:- sympathetic: SCG- Parasympathetic: through VII