Histology Exam pt 3

White pulp

- area in the spleen comprised of lymphocytes
- central arteriole passes through it

The white pulp contains what type of lymphocyte?

B cells

Stimulated B cells in the spleen produce a

germinal center

PALS

Periarteriolar lymphoid sheath
tissue that immediately surrounds the central arteriole

the PALS contains mostly ____ lymphocytes

T cells

The central arteriole branches into the

sinusoidal capillaries

SInusoidal capillaries

- allows the RBCs to exit the capillaries and enter splenic tissue
- forms the red pulp

Red pulp

Splenic tissue filled by RBCs

The red pulp contains a large amount of

macrophages

MALT

Mucosa-associated lymphoid tissue
specialized epithelia that contains lymphoid tissue

Tonsils

- MALT
- located in the oral cavity

Tonsils are surrounded by what type of epithelia?

strat. squa. nonK epith.

Tonsils are "musoca-associated" because they contain

a CT lamina propria underneath

The lymphatic tissue of the tonsils is also considered to be

diffuse; not in the lymph node or spleen

Crypt

a deep invagination of the tonsil
filled with fluid that can collect bacteria

Bone marrow is the source for

hematopoiesis

Hematopoiesis allows for

the entrance of new RBCs into the body

Hematopoietic cells

stem cells that give rise to WBCs and RBCs

Hematopoietic cells cluster is arrangements called _____ in bone marrow

cords

Leukemia

cancer of WBCs
leads to the uncontrolled division of leukocyte precursors
immature WBCs are produced and released into the blood, preventing the body from having a secure immunity

Leukemia originates in the

bone marrow

The red bone marrow contains

Megakaryocytes; large cells with lobulated nuclei that remain in the bone marrow and give rise to platelets

4 Layers of the digestive tract

1: Mucosa
2: Submucosa
3: Muscularis
4: Serosa

Digestive mucosa

- mucous membrane
- inner most lining of the digestive tract

The mucosa membrane contains

- Epithelia
- Lamina Propria
- Muscularis mucosa (sometimes)

Lamina propria

Loose CT layer that contains blood and lymph vessels

Muscularis mucosa

small thin layer of smooth muscle within the mucosa membrane
- inner circular layer
- outer longitudinal layer

Submucosa

Dense irregular CT layer that contains BVs and LVs

Muscularis layer

3rd layer of the digestive tract
- contains inner and outer orientations of smooth muscle
- contains the myenteric nerve plexus

Myenteric nerve plexus

cluster of nerve/nerve layer b/w smooth muscle layers
apart of the enteric nervous system

Serosa

outermost covering of the digestive tract
comprised of loose CT with BVs, LVs, and adipose tissue

Mesothelium

The very outermost layer of the digestive tract
outside of the gut

The mesothelium is comprised of what type of cells?

Simple squamous epithelia

The oral cavity is comprised of what type of cells?

Stratified sqaumous epith.

The cheeks, lips, and soft palate of the oral cavity is

stratified squamous nonK epith.

The gums and hard palate of the oral cavity is

stratified squamous keratinized epith.

The outer aspect of the lip

- comprised of strat. squa. Keratinized epith
- contains skin with hair follicles

Vermillion of the lip

- the red portion of the lips
- cause by the thinness of the epithelia

The vermillion of the lip does not contain

glands

The inside aspect of the lips

- contains strat. squa. nonK. epith
- beings the oral mucosa

The inside aspect of the lips is the transition from

the lip transitioning from the outer aspect to the inner aspect (nonK > K)

The blood vessels of the lip are closest to the

Lamina propria

The majority of the tounge's mass comes from

skeletal muscle

Layers of the tounge

- epithelia
- Lamina propria
- skeletal muscle

The epithelia of the tongue is

strat. squa. nonK. epith

The lamina propria of the tongue contains

BVs
LVs
Glands
Lymphoid cells

The back of the tongue contains

Lingual tonsils

Papillaie

surface elevations of the tongue
provide grip to move food around for chewing
some have taste buds

How many permanent teeth do humans have?

32

Areas of the tooth

Crown: above the gum; contains enamel
Neck: level that meets right at the gum
Root: every part that is below the gum

The gums (gingiva)

- strat. squa. nonK epith

Alveolar bone

bone that anchors teeth into the bone/bone socket

Enamel

- top most covering of a tooth
- 96% mineral

Enamel chemical components

- hydroxyapatite crystals
- ions (fluoride)
- enamelin proteins (not collagen)

Since the enamel is mineralized, what can lead to its degradation?

Acidic environments; bacteria

Ameloblasts

specialized cells that form enamel; disappear once teeth emerge from the gingiva

Dentin

- Tissue found underneath the crown of the tooth
- 70% mineralized
- contains type I collage
- contains odontoblasts

Odontoblasts

cells located in the dentin that secrete type I collagen to be mineralized into dentin

Pulp cavity

innermost portion of a tooth
contains loose CT, nerves, and BVs

Dentin tubules

- tiny spaces that contain cellular processes of odontoblasts

Peridontium

- structures that support and surround the tooth
- contains the cementum and periodontal ligaments and dental alveolus

Cementum

- surrounds the tooth up to the gingiva
- outer lining that adheres to the dentin
- secreted by cementocytes

Periodontal ligaments

- ligaments that connect the bone of the cementum to the alveolar bone
- physically holds the tooth in place

The collagen fibers of periodontal ligaments insert into

the cementum and bone socket

The periodontal ligaments have a slow/fast turnover of fibers

Fast; highest rate of collagen fiber turn over

Scurvy

- caused by a vit. C deficiency
- no vit C leads to decreased collagen production
- noticeable 1st in the gums due to the periodontal ligaments

Esophagus

A muscular tube that connects the mouth to the stomach.

The top 1/3rd of the esophagus is comprised of ________ ________ in the muscularis mucosa and muscularis layer

Skeletal muscle

The middle 1/3rd of the esophagus is comprised of ________ ________ in the muscularis mucosa and muscularis layer

blend of skeletal and smooth muscle

The bottom 1/3rd of the esophagus is comprised of ________ ________ in the muscularis mucosa and muscularis layer

completely smooth muscle

The stomach is an exo/endocrine gland?

Both

The esophagus contracts and moves food into the stomach via

peristalsis (a wave of muscle contraction)

The esophageal sphincter

where the esophagus meets the stomach
prevents food from leaving the acidic environment of the stomach

Gastric reflucx

the backward movement of acidic contents of the stomach into the esophagus via the esophageal sphincter

Food stay in the stomach for approximately

20 min

Pyloric sphincter

where the stomach meets the small intestine
controls how much digested food moves into the intestines

the pyloric sphincter has an extremely large

Muscularis

Rugae

inner foldings/ridges in the stomach

Layers of the rugae

- mucosa
- submucosa
- muscularis
- serosa

Gastric mucosa

inner most lining of the stomach
comprised of simple columnar epithelium

Gastric pit

microscopic holes/spaces in the gastric epith
lined by gastric epith
contains gastric glands that secrete molecules into the pit

Gastric glands

cells that secrete theor contents into the gastric pit

The exocrine function of the stomach comes from

the secretion of molecules into the gastric lumen/space (digestive enzymes)

The gastric mucosa epithelia is all

specialized

Gastric mucous cells

- secrete GAGs and glycoproteins
- generates a protective sugary layers

Gastric ulcers arrise from

eating away at the gastric mucous layer
prolonged exposure kills the epithelial cells, producing an ulcer

Gastric stem cells

- located further down in the pit; in the neck
- divide and become mucous and gland cells

Gastric stem cells replace cells every

4-7 days

Gastric glandular epithelia contains what cells?

- Parietal cells
- Chief cells
- Enteroendocrine cells

Parietal cells

- eosinophilic cells
- secrete HCL with stimulation by pumping H+/Cl- via proton pumps

Parietal cells are stimulated by

Gastrin
Parasympathetic NS

Gastrin

a local hormone released by the stomach
released when the stomach distends and stretches
stimulates parietal cells to produce HCl

Chief cells

- glandular cell
- produces pepsinogen and lipase
- secretes pepsinogen into the pit

Pepsinogen

- secreted in an inactive form by chief cells
- once in the pit, pepsinogen is cleaved and becomes active (pepsin)

Pepsin

the active form of pepsinogen
protease; cleaves proteins

Enteroendocrine cells

- glandular cells
- secrete other local stomach hormones including gastrin

Segments of the small intestine

duodenum, jejunum, ileum

Plica

circular folds of the SI
circumferential folds (arranged in circles)

The plica is extenstions of which digestive layer?

the submucosa; it protrudes upward into the plica

Intestinal villi

protrusions of the mucosa on a plica