easy handout on hard palate

Hard palate

It is a septum which separate nasal cavity from oral cavity.

Formation :                                                                                             

1.       Anterior 2/3 by palatine process of maxilla

2.       Posterior 1/3 by horizontal plates of palatine bone

Sutures:

There are three sutures present in hard palate.

1.      Intermaxillary suture

2.      Interpalatine suture

3.      Palatomaxillary suture

Relations:

Anteriorly it is continuous with alveolar arches and gums

Posteriorly  it is attached with soft palate

Superiorly it is formed floor of nasal cavity

Inferiorly it is formed roof of oral cavity. Inferior surface bears following structures

1.       Incisive fossa : a small pit behind the incisive teeth , it is the lower opening of two incisive canal (right and left) . incisive canals transmit terminal part of nasopalatine nerve and greater palatine vessels  

2.       Greater palatine foramen: transmits greater palatine nerve and vessel

3.       Lesser palatine foramen: transmits lesser palatine nerve and vessel

Histology of hard palate :

It has two surfaces:

Histology of nasal surface of hard palate:

It is lined by pseudo-stratified ciliated columnar epithelium.

This epithelium contains intraepithelial gland.

Sub-endothelial connective tissue contains glands, blood vessels and lymph vessels.

 The epithelium and the sub-epithelial connective tissue are collectively known as the mucoperiosteum, which is firmly attached to the bony shelf of the palate.

Masticatory mucosa :

It is found in the gingival (gums) and the hard palate

1.      Lining epithelium: Keratinized stratified squamous epithelium and in some place parakeratinized .

Keratinized epithelium of hard palate likes skin but stratum lucidum layer is absent.

Criteria of parakeratinized stratified squamous epithelium :

·         Superficial cells have nuclei like keratinized stratified squamous epithelium but nuclei are pyknotic (highly condensed) remain until the cell is exfoliated and

·         cytoplasm is not intensely stain by eosin

  Rete ridges are present in epithelium they are deep invagination of epithelium with

   subepithelial connective tissue  

2.      Lamina propria is formed by connective tissue contain dense collagen fibres, blood vessels and nerves. Deep to lamina propria contain reticular fibre rich dense connective tissue which firmly bind the palatine mucosa to the periosteum. Hard palate is also containing large deposits of adipose tissue at its anterior part and mucous gland at its posterior part.

Blood supply : greater palatine artery (from the third part of the maxillary artery) which emerges from the greater palatine foramen and passes forwards around the palate (lateral to nerve) to enter the incisive canal and pass up into the nose

Vein: corresponding vein drain into pterygoid venous plexus and pharyngeal plexus.

Lymphatic drainage: retropharyngeal  and deep cervical lymph nodes

Nerve supply : by branches of maxillary nerve via pterygopalatine ganglion

1.       Anterior part is supplied by two nasopalatine nerves

2.       From incisive fossa to rest of the posterior part is supplied by greater palatine nerve .

Development:

1.       Primary palate develops  from intermaxillary prominence

2.       Secondary palate develops from palatine shelves from the maxillay prominence

Two palatine shelves of maxillary prominence unite and fused with  primary palate.

Summary of sympathetic nervous system

Sympathetic nervous system is the part of autonomic nervous system .

Functionally Nervous system can be divided into two part
somatic nervous system and autonomic nervous system .
Sympathetic system is the part of autonomic nervous system

•Like somatic nervous system autonomic nervous system has two parts •Motor part of autonomic system innervate smooth muscle, cardiac muscles  and most of the glands of the body
•Sensory part of autonomic system carry sensory impulse from viscera to the brain . Sensory parts of autonomic system usually ran along the sensory system of somatic system so we often perceive visceral pain in the body wall .

short description of sympathetic nervous system

Topics	Sympathetic nervous system
Out flow	it is also known as thoraco lumbar outflow T1 to L 2
Pre ganglionic fibres	Short
Post ganglionic fibres	Longer
Ganglia	Para vertebral sympathetic ganglia  is away from the target organ
Location of pre-ganglionic neuron	•       Lateral horn cells of all thoracic segments and upper two or three lumbar segments of spinal cord
Location of post-ganglionic neuron	•       Lateral: sympathetic trunk •       Collateral : coeliac, superior mesenteric ganglia •       Terminal ganglia: supra-renal medulla
	This system activate during emergency and works during stress and strain for fight or flight
	Liberates non adrenaline at postganglionic ending except eccrine type of sweat glands and most of the blood vessels of skeletal muscle
	This system is not essential for to life
Urinary bladder	It is the nerve of filling It contract (close) urethral sphincter and relax detrusor muscles
Heart	Cardiac muscles cells : increase force of contraction Coronary vessels :  vasodilator ( so supply of nutrition and oxygen increase in cardiac muscle cells  )
Lung:	Bronchodilator / Trachealis muscles relax so diameter of trachea increase Decrease secretion of tracheal glands
Stomach	Gastric musculature (smooth muscle cells ) is relax  but smooth muscle cells at the pyloric sphincter is contract (closer of pyloric sphincter )
Small gut	Inhibit peristalsis Vasoconstriction (vaso motor)
Summary : effect	•       Produce mass reaction •       Cutaneous blood vessels undergo vasoconstriction but, skeletal and coronary vessels are dilated thus supplying more blood to the muscles, heart, brain. Heart rate is increased, blood pressure and blood sugar are elevated , pupil and bronchi are dilated. Intestinal peristalsis is suppressed and the sphincters of gut are closed.
Eye	Pupil dilates
*Uterus	Uterine contraction Vasoconstriction
Salivary glands	_
Pancreas	_
Gastric glands	_
Adrenal glands	secretomotor
Vessels of Skeletal muscle	Vasodilatation
Sweat gland	secretomotor
Afferents	Convey most of the visceral pain except pelvic organ
Cells of origin of afferents fibres	Dorsal root ganglia of T 1 to L1/L2
Central control	Posterior part of hypothalamus

Summary of parasympathetic ganglion of head and neck region

Para-sympathic ganglion of head and neck

Topics	Ciliary	Pterygopalatine
Nucleus of origin	Edinger-westphal nucleus in midbrain	Superior salivary nucleus in pons
Site of ganglion	Posterior lateral to optic nerve in orbit	Pterygopalatine fossa inferior to maxillary nerve
Preganglionic pathway	3rd nerve via branch to inferior oblique muscle	Facial nerve via greater superficial petrosal nerve & nerve of pterygoid canal
Post-ganglionic pathway	Short ciliary nerves	Greater & lesser palatine nerves &  sphenopalatine nerves Lacrimal nerves
Organ of destination	Ciliary body Sphincter pupillae	Palate Nose Lacrimal gland

Topics	Sub-mandibular	Otic
Nucleus of origin	Superior salivatory nucleus in pons	Inferior salivatory nucleus in medulla
Site of ganglion	On hyoglossus muscle inferior to lingual nerve	Inferior to foramen ovale outside skull
Preganglionic pathway	Facial nerve via chorda tympani & lingual nerve	Glossopharyngeal nerve via tympanic & lesser petrosal branches
Post-ganglionic pathway	Lingual nerve	Auriculotemporal nerve
Organ of destination	Sublingual & submandibular glands	Parotid glands

Ossification : easy and brief description

Ossification: it is the process of bone formation

Classification of ossification centre:

1. A primary ossification center is the first area of a bone to start ossifying.

 It usually appears during intra-uterine life in the central part of each developing bone.

Exception: carpal bones of hand

 In long bones the primary ossification centers appear in the diaphysis/shaft and in irregular bones the primary centers appear usually in the body of the bone.

All long bones have only one primary center but some irregular bones such as the hip bone and vertebrae have multiple primary centers.

2. Secondary ossification centre: A secondary ossification center is the area of ossification that appears after the primary ossification center has already appeared - most of which appear during the postnatal and adolescent years. Most bones have more than one secondary ossification center. In long bones, the secondary centers appear in the epiphyses (upper and lower end).

Classification of mechanism of ossification

Membranous ossification:

Ex: head and neck: parietal bone, frontal bone, maxilla, zygomatic,

Sup extre: clavicle

Cartilaginous ossification: all vertebrae, all ribs, sternum, scapula, all bones of upper limb except clavicle, all bones of lower limb

Membrano-cartilaginous ossification:

Occipital: membranous ossification area above the highest nuchal line, rest of the parts arises from cartilaginous ossification  

Sphenoid: membranous ossification above the lateral part of greater wing and pterygoid process except the hamulus, rest of the part arises from cartilage,

Temporal: membranous ossification – squamous part and tympanic part, rest of the parts arises from cartilage,

 Mandible: cartilaginous ossification anterior part of body and part of ramus above mandibular foramen, rest of the body arises from membranous ossification

Name of bone	Primary ossification center	Secondary ossification center
Clavicle	Two	One for sternal end
Humerus	One for shaft	Three for upper end – head , greater & lesser tubercle Four for lower end – lateral & medial epicondyle, capitulum, trochlear
Radius	One primary ossification center for shaft	One for upper end One for lower end
Ulna	One primary ossification center for shaft	One for upper end One for lower end
Carpal bone	One primary ossification center which appear after birth	No secondary ossification centre
Metacarpal bone	One primary ossification center for shaft	One 2nd ossification centre :  base of  1st metacarpal bones is ossified from 2nd ossification center Heads of  2-5 metacarpal bone are ossified from 2nd ossification center
Phalanges	One primary ossification center for shaft and head	One 2nd ossification center for base  of each phalanx

Lower limb

Name of bone	Primary ossification center	Secondary ossification center
Hip bone	Three – ilium, ischium, pubis	5 secondary ossification center
Femur	One for shaft	Three for upper end – head , greater & lesser trochanter One for lower end
Tibia	One primary ossification center for shaft	One for upper end One for lower end
Fibula	One primary ossification center for shaft	One for upper end One for lower end
Tarsal bone (except calcaneus)	One primary ossification center	No secondary ossification centre
Calcaneus	One primary ossification center	One secondary ossification centre
Metatarsal bone	One primary ossification center for shaft	One 2nd ossification centre :  base of  1st metatarsal bones is ossified from 2nd ossification center Heads of  2-5 metatarsal bone are ossified from 2nd ossification center
Phalanges	One primary ossification center for shaft and head	One 2nd ossification center for base  of each phalanx