Histology 2 Midterm: A Detailed Guide on How to Eat a Sandwich

Mucosa

Submucosa

Muscularis Externa

Adventitia or Serosa

(feel free to add "tunica" in front of any of these)

What are the 4 LAYERS of the general organization of the GI tract?

Epithelium

Lamina Propria

Muscularis mucosa

What are the SUBLAYERS of Mucosa?

Inner circular layer

Outer longitudinal layer

What are the SUBLAYERS of Muscularis Externa

Connective tissue

Lamina Propria is the ____ layer underneath/around the epithelium

Independent movement of mucosa

Muscularis mucosa are layers of smooth muscle for what function?

Large blood vessels and nerves (Meissner's plexus)

Submucosa is usually DICT that contains ________ as well as glands

Submucosal (Meissner's) plexus

Myenteric (Auerbach's) plexus

What are the 2 layers of the enteric nervous system?

Secretory functions

What is the main function of the Submucosal plexus?

Motor function (peristalsis)

What is the main function of the Myenteric plexus?

Two layers of smooth muscle (inner circular/outer longitudinal)

Myenteric plexus between muscle layers

What are the layers of Muscularis Externa?

Serosa: Connective tissues covered by Simple Squamous epithelium

Adventitia: Connective tissue continuous with surrounding fascia (It's Adhered)

What are the definitions of Serosa and Adventitia

It's own layer

Else: lamina propria - submucosa or mucosa - submucosa

If muscularis muscosae is present, submucosa is considered ...

Quizzy Pop

FALSE. THIS WILL NOT BE TESTED.

T/F: You should spend time understanding the differences between sections in the villi

Memorize this if you want a 100%

Make this make sense to yourself

Brachydont

- low crown, no further growth

Hypsodont

- high crown, keep growing

What are the two types of teeth?

Anatomical crown (covered by enamel)

Clinical crown (visible portion of tooth)

What are the two portions of a crown?

Cementum

Anchor tooth to bone

What is the root covered in?

What is its job?

Junction of crown and root

Enamel ends, cementum begins

Attachment of gingival epithelium to tooth

What is the identifying feature of the neck?

Secreted by ameloblasts

Hardest substance in body

How is enamel made?

What is it's main characteristic?

Dentin

Second hardest substance

What is the tooth's internal template?

Secreted by odontoblasts

How is dentin made?

Dentinal tubes

Extend the entire length of dentin, with sensory nerve endings

What are the open channels in dentin called?

Cementum

Cementoblasts/Cementocytes (Peripheral/central)

Similar hardness to bone

What coats the outer surface of the root?

What secretes and maintain cementum?

Pulp cavity

What is the space filled with LCT, nerves, and vessels in the tooth?

Lined by odontoblasts (that secrete dentin)

Decreases cavity size as dentin is secreted

What lines the pulp cavity?

How do they affect the cavity's size?

Pulp chamber (in crown)

Root canal (in root)

What are the subdivisions of the pulp cavity?

Cutaneous mucous membrane of gingiva (gums)

Mucosa lined by stratified squamous epithelium with supporting DICT is ...

Gingival sulcus

What is the potential space between gingiva and anatomical crown

Periodontal ligament

Made of type I collagen

What ligament suspends the tooth in the alveolus, acting as a shock absorber?

Sharpey's fibers

What are the anchor fibers in the alveolar bone and cementum

Jaw-jerk relflex

Proprioceptive nerve endings sense tooth location, and when you bite too hard, what reflex is involved causing the muscles to relax?

Blue: Crown

Yellow: Root

What are the blue and yellow sections?

Pulp cavity

Dentin

What is outlined in blue in the center of the tooth?

What substance makes up the yellow area?

Cementum, divided into cellular and non-cellular

Bone

What is the green layer representing under the blue?

What is scribbled in yellow?

Red: Gingival sulcus

Yellow: Junctional Epithelium

Blue: Cutaneous Mucous Membrane

Red area?

Yellow layer?

Blue structure?

Dentinal tubules

Pre-dentin (will not be asked to ID)

What are the yellow lines indicating?

What is the blue arrow pointing to?

Odontoblast layer

What layer is between the blue lines?

Cementum

Periodontal ligament

What is the layer in blue?

What is the structure in red?

Sharpey's fibers

What are the green lines representing in the periodontal ligament?

Cementocytes/blasts

Cementum

What are the cells in green?

What are they in?

Ameloblasts

What are destroyed in brachydont teeth but not in hypsodont teeth that allow for continued growth?

The entire surface of the tooth (covers enamel)

Where is cementum deposited on a hypsodont tooth?

Infundibulum

The surface invagination lined by enamel and covered by cementum is called the ...

Enamel crest

When wearing reaches the dentin (which is weaker than enamel), leaving a depression, the projected enamel is called an ...

Ectoderm and mesoderm

Where do teeth develop from?

Ameloblasts

Neural crest derived odontoblasts from mesoderm

(whatever that means)

How is enamel produced?

How is dentin produced?

Inner enamel epithelium forms ameloblasts that produce enamel

Stratum intermedium (cause previous to produce ameloblasts)

Stellate reticulum (Cushion to protect ameloblasts)

Outer enamel epithelium (outer boundary of enamel organ)

What are the layers of the enamel organ?

1) Stratum intermedium makes inner enamel epithelium to become ameloblast

2) Ameloblast makes mesenchymal cells on dental papilla to become odontoblasts

3) Odontoblasts secrete dentin first

4) Ameloblasts secrete enamel on top of dentin

What are the steps of enamel and dentin formation?

Red: odontoblasts

Yellow: Dentin/pre-dentin

Green: Enamel

Purple: Ameloblasts

Behold, a developing tooth. Label the pretty colors

Stellate reticulum

What is highlighted in blue in this developing tooth?

Purple: Ameloblasts

Green: enamel

Yellow: dentin

Red: odontoblasts

Note, stellate reticulum to left and pulp cavity to right

What are the 4 colored layers?

Secretion goes to mouth by a duct

What is the key characteristic of an exocrine salivary gland?

Don't lose cytoplasm during product release

Recall the key characteristic of a merocrine gland

Major: Gross(ly visible) and away from the mouth

Minor: Glands in the oral cavity

Difference between major and minor glands?

Mucous (highly viscous) and serous (watery)

Recall how to classify glands by nature of the product

Round nucleus at base of cell, cells arranged in acini

Describe the structure of a serous salivary gland

Flat nucleus at base of cell, may be acinus or "tube-like" arrangement

Cytoplasm does not stain well

Describe a mucous salivary gland

Mucinogen (precursor to mucous)

What is the secretory product of mucous SG?

Mixed SG

Specifically a serous demilune

What's this?

- Individual ends of serous and mucous empty into a common duct

- Integrated end pieces, with a cap of serous cells (demilune)

What are the two arrangements of mixed SG

Myoepithelial (basket) cells

What cells have contractile properties and surround the base of secretory cells to facilitate movement and prevent luminal pressure from damaging the cells?

Green: lobules

Yellow: Septa

Purple: Lobe

Outlined in green are individual ____

They are separated by ____

The purple lines are indicated a ____

Salivary gland ducts

The channels transporting secretions from acini lumen to the mouth are ...

Intercalated ducts (in lobules)

Intralobular (striated) ducts (in lobule)

Interlobular duct (between lobules)

Lobar duct (between lobes)

Main duct (opens into body)

What are the duct categories, from small to large?

Simple cuboidal

4-8 cells (cross section)

Direct connection to acini

What are the characteristics of an intercalated duct?

Simple columnar

Striated appearance

Buffers saliva pH with bicarbonate

Characteristics of intralobular (striated) ducts

Green: Intercalated duct

Red: Striated duct

ID Ducts

Striated duct

Infoldings of basal membrane

ID duct

What are the green lines representing?

Interlobular: simple columnar or stratified cuboidal

Lobar + Main: Stratified epithelium

What kind of epithelium do the largest three ducts have?

Interlobular duct

Septa

ID duct

What is it surrounded by?

There is no muscularis mucosae

Why are the lamina propria and submucosa combined in the mouth?

Mouth, cheek

Hard/soft palate

Gingiva

Where is cutaneous mucous membrane found?

Mucocutaneous junction

What is the site of transition between epidermis and mucous membrane?

Intrinsic: change shape

Extrinsic: move

What are the roles of intrinsic and extrinsic muscles of the tongue?

Root

body

Apex

Subdivisions of the tongue?

Papillae

Projections from tongue surface are...

Move food, groom, taste

Functions of papillae

Fungiform

Foliate

Vallate

Chef's love using Fungi, Foliage, and Vegetables!

Which papillae have taste buds?

Rostral 2/3,

Filiform keratinized in cat/cow

Fungiform is mushroom shaped

Where are filiform/fungiform papillae?

Filiform

Type of papillae?

Fungiform

Taste bud

Type of papillae?

What is in green?

Taste bud

Taste pore

What is highlighted in green?

What is the red arrow pointing to?

Horses

What animal are conical papillae NOT in?

(Circum)Vallate

ID Papillae

Foliate

Cow

ID. Name animal it's absent in

Blue: conical

Red: vallate

Yellow: Von Ebner's glands

ID pretty colors

Papillae on lateral margins of tongue to facilitate nursing

What are marginal papillae for?

10 days

What is the average lifespan of taste buds?

Rugae, allowing for expansion

What are the longitudinal folds/what are they for in the esophagus?

Stratified squamous non-keratinized (carnivores)

Mucosa: What epithelia is present in the esophagus

Pepsinogen

Lysozyme

Mucous

Submucosa: Seromucous glands in the esophagus secrete what?

Dogs (+ cows): entirely skeletal

Cats (+ horses): 2/3 skeletal + 1/3 smooth

Muscularis externa: What is the muscle composition of the esophagus in dog/cats?

Adventitia

The cervical portion of the esophagus is ...

Orange: Mucosa

Red: Non-keratinized stratified squamous epithelium

Green: lamina propria

Blue: Muscularis mucosae

Lumen is above

Label the layer (orange)

Label the sublayers (RGB)

Orange: Submucosa

Blue: Seromucous gland duct

What layer is below the mucosa (orange)

What glands are here (blue)

Orange: Muscularis externa

- Top: Inner circular layer

- Bot: Outer longitudinal layer

Serosa/adventitia

What layer is below submucosa (orange)

What sublayers does it have?

What is this layer above?

Cutaneous mucous membrane

What lines the non-glandular region of the stomach?

Cardiac/fundic/pyloric gland regions

What are the glandular regions of the stomach?

Rumen

Reticulum

Omasum

3 parts to the non-glandular stomach of ruminant?