Head and Neck Intro

Question 1

What are some functions of the head and neck?

Answer 1

Houses the special senses (5 senses)

Able to conduct the acquisition of food, perform salivation, mastication and initiation of deglutition (moving food down oesophagus)

Use the special senses in conjunction with other activity

To protect the brain and cervical spinal cord (Central nervous system)

To communicate through voice and facial expression

Question 2

What are the special senses found in the head&neck region?

Answer 2

Taste
Smell
Sight 
Hearing 
Touch

Question 3

What are the 3 main glands in the head and neck?

Answer 3

Paratoid, submandibular and sublingual gland.

Question 4

What nerve runs through the parotid gland?

What does it supply?

Answer 4

Motor part of the facial nerve

Does not supply this gland, it supplies the muscles of facial expression.

Question 5

What supplies the parotid gland?

Answer 5

By the glossopharyngeal nerve (parasympathetic division) which is one of the cranial nerves.

Question 6

What are the sublingual and submandibular glands supplied by?

Answer 6

Sublingual and submandibular glands are supplied by the parasympathetic part of the facial nerve. (Not the motor part shown).

Question 7

What cranial nerve supplies the tongue?

Answer 7

Hypoglossal nerve (12th cranial nerve)

Question 8

What muscles are involved in mastication?

Answer 8

This involves the temporalis muscle and the massetor muscle. These move the mobile up and down and back and forth.

Under the massestor, we have pterygoid muscles which move the mandible during chewing also.

Question 9

What cranial nerve supplies the muscles of mastication?

Answer 9

Muscles of mastication are supplied by the mandibular division motor component of the trigeminal nerve (3rd part of the nerve V3).

Question 10

How does ossification of the skull occur?

Answer 10

Direct conversion of mesenchymal tissue into bone.

Firstly, get the ossification occurring in outer layers. Calcification of this bone occurs via osteoblasts. Sutures form and then we get rapid growth of cranial bone takes place via the proliferation of osteoblasts.

Question 11

Name some of the important bones of the skull

Answer 11

Parietal bone
Frontal bone
Zygomatic bone
Sphenoid bone
Maxillary bone
Mandible bone 
Temporal bone
Occipital bone 

(Sphenoid bone - gives rise to many places of attachment.
Foramen - structure through which nerves, arteries and veins pass through. Not all Forman have all 3 of these, can have just one.)

Question 12

Give details on how the brain and spinal cord is protected

Answer 12

Within the skull lies other connective tissues (the meningeal layers, partially the dura mata protects intercranical regions).

Protection of the brain is maximised by the structure.
Spinal cord in neck is housed within the cervical vertebrae which gives it protection.

Question 13

Don’t need to learn these but give some names of muscles of facial expression

Answer 13

Frontalis 
Nasalis 
Buccinator
Platysma 
Orbicularis oris

Question 14

Where are expression muscles found in the face?

Answer 14

These expression muscles lie just under skin in the dermis. There are many of them to allow for all the movements. They allow for the facial expression.

Question 15

What nerve supplies the muscles of facial expression?

Answer 15

Motor component of the facial nerve which comes through the parotid gland.

Question 16

What is the larynx made up of?

Answer 16

It is made up of cartilage and there are 3 unpaired and 3 paired cartilages. These can move to bring about different functions in swallowing for example so food goes into trachea. Also for movement of them to help create sound. Uses air with runs through it and manipulation of cartilages to create the different sounds.

It is supplied by branches of the motor component of the vagus nerve (tenth cranial nerve).

Tenth cranial nerve also has a large parasympathetic function throughout body. This is no the motor component.

Thyroid cartilage is part of the larynx. Larynx has the thyroid gland above it. This gland is an endocrine gland critical for metabolism and growth. The gland is very susceptible to pathologies e.g. under and over activity and cancers.

Parathyroid glands - associated with thyroid glands, involved in calcium homeostasis in the body. Can be disrupted during pathology or when they thyroid gland undergoes surgery.

Question 17

What are the cranial nerves called and list their function?

Answer 17

1 - Olifactory nerve for smelling

2. Optic nerve for detecting light
3. Oculomotor nerve for moving eyes
4. Trochlear nerve for moving the eyes
5. Trigeminal nerve for giving sensation to face, helping with chewing and controlling muscles in ear
6. Abducent nerve for moving the eyes
7. Facial nerve for moving the face, giving taste sensation. by supplying anterior 2/3 of tongue.
8. Vestibulocochlear nerve for hearing and balance
9. Glossopharyngeal nerve for moving throat on swallowing and sensing taste
10. Vagus nerve for many things in body
11. Accessory nerve for raising the shoulder
12. Hypoglossal nerve for moving tongue

Question 18

Give some examples of foramen in the brain

Answer 18

These are holes in bone to allow transmission of structures leaving or entering the skull.

The foramen magnum is where the spinal cord will communicate with brain stem.

Jugular foramen - where the internal jugular vein begins. Collects blood from intercranial region and goes through the dural venous sinuous and then as there is an exit from the skull here, it exit is used. Internal jugular vein and the cranial nerves 9, 10 and 11 go through the jugular foramen.
Forman ovale - allows third part of trigeminal nerve (mandibular division) to leave the cranium and supply the muscles for mastication.

Foramen rotundum - allows second part of the trigeminal nerve to leave.

Question 19

What is the typical shape for muscles of the neck?

Give some examples

Answer 19

Most muscles are long and slender and have different nerve supplies.

Ternocleidomastoid muscle - muscle running on left side of neck. Supplied by the 11th cranial nerve. The trapezius muscle is supplied by the 11th cranial nerve also.

Other muscles are either supplied by cervical nerves or muscles under mandible e.g. digrastric or mylohyoid, are supplied by cranial nerves.

Some muscles in neck region therefore are supplied by cranial nerve 11, cervical nerves (1,2, and 3) and muscles above the hyoid are mainly supplied by the cranial nerves.