Lecture 3 Oralfacial Structures Flashcards
OROFACIAL GLANDS
GLAND:
A structure that produces a secretion to regulate body’s normal functioning.
EXOCRINE GLAND:
A gland with a duct that releases secretions, such as sweat or saliva directly to target areas.
ENDOCRINE GLAND:
A ductless gland that secretes hormones directly
into the blood stream.
THYROID GLAND
THYROID GLAND
THYROID GLAND
• Largest endocrine gland, very vascular.
• Consists of 2 large lobes connected by an isthmus in the middle.
• Secretes hormones (thyroxine)
that control and regulate metabolism and growth.
• Located below the larynx on either side and in front of the trachea.
• Is not visible but should be palpated during the extra oral exam - should exhibit mobility and move superiorly when client swallows.
STRUCTURE OF THE THYROID GLAND
• CAPSULE - connective tissue that surrounds the thyroid.
• SEPTUM (plural: septa) - separates the gland into larger lobes and smaller lobules.
• LOBULES - composed of follicles:
irregularly shaped sphere-like masses that are embedded in a meshwork of reticular fibres.
• FOLLICLES - a cavity filled with colloid, layered with simple cuboidal epithelium.
• COLLOID - a stiff material reserved for the future production of thyroxin.
PARATHYROID GLANDS
• Consist of 4 to 8 small endocrine glands, two on each side, close to the thyroid gland or even inside it on its posterior surface.
• These glands are not visible or palpable during an extra oral examination of a patient.
• Secrete parathyroid hormone directly into the bloodstream to regulate calcium and phosphorus levels.
• May alter the function of the thyroid gland if they are involved in a disease process.
Thyroid and Parathyroid Glands
LYMPHATIC SYSTEM
• Part of the immune system, helps defend the body against disease.
• Closely related with the cardiovascular system.
• Transports excess tissue fluid to the bloodstream.
LYMPHATIC VESSELS AND CAPILLARIES
LYMPH
• Lymph: Tissue fluid that drains from surrounding region into lymphatic vessels.
• Increased pressure within interstitial spaces forces some fluid into the lymphatic capillaries.
• It transports foreign particles to the lymph nodes and returns protein molecules into the bloodstream.
LYMPHATIC PATHWAYS
- LYMPHATIC CAPILLARIES:
- microscopic close ended tubes that extend into interstitial space, that receive lymph through their walls. - LYMPHATIC VESSELS:
- formed by merging of lymphatic capillaries, then lead to lymph nodes and then merge into lymphatic trunks.
- they have walls similar to veins, and valves to prevent backflow of lymph (lymph goes in but not back out: one-way valves). - LYMPHATIC TRUNKS AND
COLLECTING DUCTS:
- lymphatic trunks drain lymph from large body regions and lead to two collecting ducts in the thorax.
- collecting ducts join the subclavian veins.
Lymphatic Pathways
Flow Chart
LYMPH NODES
• Bean-shaped bodies grouped in clusters along the lymphatic vessels.
• Lymph nodes are composed of lymphocytes and macrophages:
- these cells filter toxic products from the lymph to prevent entry into the vascular system.
LYMPH NODES: STRUCTURE
Capsule: a band of connective tissue surrounding the node.
-Lymph flows into the lymph nodes through afferent vessels.
- Lymph flows out of the lymph node through efferent vessels where a small depression, called the hilus, is present.
Trabeculae:
Trabeculae: extensions of connective tissue from the capsule into the node that divide the node into nodules or follicles
Germinal Centre
Germinal center: the middle of each nodule where masses of immature lymphocytes mature into B-cells and aid in the production of plasma cells.
LOCATION OF LYMPH NODES
They occur in groups or chains along the paths of larger lymphatic vessels.
Mainly located in:
cervical (head/neck)
auxiliary (armpit)
inguinal (groin)
regions.
Lymph Nodes of the Head
Lymph Nodes of the Neck pg. 7
Pic of nodes
INTRAORAL TONSILAR
TISSUE
3 Types
3 TYPES:
1. PALATINE TONSILS
2. LINGUAL TONSILS
3. PHARYGEAL
TONSILS
INTRAORAL TONSILAR TISSUE
1) PALATINE TONSILS:
Two rounded masses located between anterior and posterior faucial pillars.
-• Each mass contains fused-together lymphatic nodules that have germinal centers.
• Each tonsil has 10 to 20 epithelial invaginations, or grooves, which penetrate deeply into the tonsil to form tonsillar crypts (deep groove which increase surface area.
INTRAORAL
- TONSILAR TISSUE
2) LINGUAL TONSILS:
• Layer of indistinct diffuse lymphoid tissue located on the base of the dorsal tongue, behind circumvallate papillae.
Tongue
Tip of tongue Fungiform papillae
INTRAORAL TONSILAR TISSUE
3) PHARYGEAL TONSILS:
• Found behind uvula, on the superior and posterior walls of the nasopharynx forming an incomplete ring of tissue called Waldeyer’s ring.
• If they become enlarged (usually in children), they are referred to as adenoids.
NASAL CAVITY
• Anterior region opens up to outside through two nostrils (nares) and is divided by the nasal septum (composed of cartilage and bone)
what kind of cartilage??
• Posterior region opens up to the nasopharynx.
• Median wall is called the septum.
• Lateral wall has 3 projecting structures called the conchae which extend inward. Underneath each conchae, there is a passageway to paranasal sinuses and nasolacrimal ducts (tear ducts).
The posterior part of the nasal cavity communicates with the nasopharynx and respiratory system.
LATERLA VIEW OF NASAL
CAVITY
Histology of the Nasal Cavity
Histology of the Nasal
• The nasal cavity is lined by a respiratory mucosa, which is ciliated pseudostratified columnar epithelium.
• Within the epithelium are goblet cells (secrete mucin) which rest on the basement membrane.
NASAL CAVITY - pg. 144
Goblet cells - secrete mucin to moisten and humidify the nasal
cavity and trap foreign materials.
Cilia - trap and move foreign materials to either be swallowed or
expelled.
Lamina propria - is very vascular and warms the air we breath.
Olfactory mucosa - is a specialized area, which caries receptors
for the sense of smell.
Erectile tissue - covers each of the conchae and is responsible for great engorgement (fills with blood) of one of the openings every 30 - 60 mins to allow the tissue to recover from dryness caused by breathing.
PARANASAL SINUSES
• Paired, air filled, mucous-lined cavities in the head and cheek bones that drain into the nasal cavity through openings on the lateral nasal wall.
-• 4 pairs:
- frontal, ethmoidal, sphenoidal and maxillary sinuses.
• Function: lighten the scull bones, add resonance to the voice, moisten the nasal cavity.
• Lined by respiratory mucosa (ciliated pseudostratified columnar epithelium), thinner with less goblet cells than the nasal cavity mucosa.
Also has thinner lamina propria and no erectile tissue.
A collection of similarly specialized cells in the body is termed a(n):
Tissue
Simple cuboidal epithelium is:
Single layer of cube-like cells.
Basement membrane is an acellular structure composed of 3 layers.
True
The most common cell type found in all connective tissue is:
Fibroblast
This connective tissue stores fat and acts as a heat insulator:
Adipose tissue
Cartilage lacks direct blood supply and is slow to heal.
True
Osteoclasts are:
Bone-resorbing cells
Endochondral ossification uses interstitial growth from pre-existing cartilage model.
True
Smooth muscle is controlled by voluntary activity:
False
Afferent nerve caries
information from PS to CNS:
True
Exocrine gland is:
A gland with a duct.
Lymphatic system is part of the immune system, and is closely related with the cardiovascular system.
True
These structures occur in groups or chains along the paths of larger lymphatic vessels, and actively filter out lymph:
Lymph Nodes
Ciliated pseudostratified columnar epithelium is found in:
A. The nasal cavity
B. Paranasal sinuses
C. All of the above
D. None of the above
C All the above
Where are the palatine tonsils located?
Between anterior and posterior faucial pillars.
