Lecture 3 Histology

Question 1

Name the 4 basic tissue types.

Answer 1

Epithelial Tissue
Connective Tissue
Muscle Tissue
Nervous Tissue

Question 2

Where are epithelial tissues found?

Answer 2

■Barrier/Covers or lines every body surface and all body cavities. External and internal lining of many organs.
■Oral Mucosa (lining of the cheek), Nasal Cavity

Question 3

What are the functions of epithelial tissue?

Answer 3

■Physical protection- Epidermis, esophagus
■Selective permeability- alveoli of lungs, lining of blood vessels, kidney tubules, intestines
■Secretion - glands, intestines
■Sensation - Epidermis, nerve endings

Question 4

Describe the special characteristics of epithelial tissue that distinguishes it from other tissue types.

Answer 4

■Cellularity - It’s made up of lots of cells, with very little space between them (extracellular matrix).
■Polarity - Have two sections: a top(apical surface) which is free and unbound, and a bottom(basilar surface) which is bound to the basement membrane.
■Avascularity - No blood flow directly to cells. They get their nutrients from the connective tissue below.
■Innervation - Does contain nerve endings
■Regeneration - Capable of rapid division to replace old or worn out cells
■Attachment- Bound to basement membrane.

■AIR CAP (Avascular, Innervated, Regeneration, Cellularity, Attachment (to basement membrane), Polarity)

Question 5

Name and describe the types of intercellular junctions found in epithelial tissue.

Answer 5

• Tight Junction - Closely attach adjoining cells and are closest to apical surface. Impermeable
• Adhering Junction - Hold cells together, usually more basal than tight. Like belt around cells.
• Desmosomes - Junctions that are usually found at stress points.
• Hemidesmosomes - half desmosome, hold cell to basement membrane.
• Gap Junction - Connects cytoplasms of two cells, allowing exchange of molecules.

Question 6

Describe how epithelial tissue is classified according to cell shape and layers.

Answer 6

■Layers
•Simple epithelium - has one layer
•Stratified epithelium - anything more than one layer
■Shape
•Squamous - basic flat cell
•Cuboidal - cube like
•columnar - column like

Question 7

What is the basic structure, function, and location of the following epithelial tissue.
Simple squamous

Answer 7

Flat, circular, single line
Diffusion and filtration
Found in the lung air sacs(alveoli), lining of blood vessels and serous membranes.

Question 8

What is the basic structure, function, and location of the following epithelial tissue.
transitional

Answer 8

Multiple lines of squares on top of each other that can go flat or go back to square shaped
Distention and relaxation of urinary structures
Found in ureters, bladder, and urethra.

Question 9

What is the basic structure, function, and location of the following epithelial tissue.
simple cuboid

Answer 9

Cube shaped, single line
Absorption and secretion
Found in kidney tubules and glands. (Longer cells provide more room for cellular machinery)

Question 10

What is the basic structure, function, and location of the following epithelial tissue.
simple columner

Answer 10

Rectangle cube shaped, single line
Absorption, secretion, and movement(if ciliated, which is in the uterine tubes).
Found in stomach, small intestine, and large intestine.

Question 11

What is the basic structure, function, and location of the following epithelial tissue.
stratified squamous

Answer 11

Multiple lines of flat circles on top of each other
Protection
Found in oral cavity, pharynx, esophagus, vagina, anus, epidermis of skin.

Question 12

What is the basic structure, function, and location of the following epithelial tissue.
pseudostratified columner

Answer 12

Multiple lines of rectangle cube shapes on top of each other
Protection, Movement(if ciliated)
Found in the respiratory tract.

Question 13

Explain the basic differences between endocrine glands and exocrine glands.

Answer 13

Endocrine - Ductless, secrete products directly into interstitial fluid and bloodstream. Release hormones wherever they are.
Exocrine - Secrete products through ducts onto an epithelial surface(your face, for example). Acinus is the secretory portion and the Duct is the conducting portion. 3 types of exocrine glands

Question 14

Describe the three different types of exocrine glands (merocrine, holocrine and apocrine).

Answer 14

• Merocrine - watery sweat, tears, and saliva. Products excreted by secretory vesicles via exocytosis (ie, the cell produces the product then transports it out).
• Holocrine - The entire (holo) cells disintegrate and become the product(ie, oil glands). Multiple branches.
• Apocrine gland - A part of the cell (apo) breaks off and becomes the product. Thick smelly sweat (armpits and other crevice-like areas) and milk.

Question 15

What are the basic characteristics of connective tissue?

Answer 15

Connective tissue is in some ways opposite of epithelial tissue. Connective tissue has very few SPARSE cells in a large extracellular matrix. It contains protein fibers and ground substance.

Question 16

What are the basic functions of connective tissue

Answer 16

Physical protection
Support and structural framework (bones)
Binding of structures
Storage
Transport (blood)
Immune protection

Question 17

What is meant by the term extracellular matrix?

Answer 17

Everything outside of the cell. Includes ground substance and protein fibers.

Question 18

What is meant by the term ground substance?

Answer 18

Basically the liquid portion of the extracellular matrix, mostly made up of water and carbohydrates, but does have some protein components as well.

Question 19

What are the two types of connective tissue proper?

Answer 19

Loose Connective Tissue (few fibers, more ground substance)

Dense Connective Tissue (more fibers, less ground substance)

Question 20

What is the basic structure and contents of the supportive connective tissue types (cartilage and bone) and fluid connective tissue (blood).

Answer 20

■Cartilage
◦Semisolid matrix
◦Containing chondrocytes.
■Bone
◦Calcified matrix 
◦Containing osteocytes.
■Blood
◦Soluble protein fibers and watery ground substance. ◦Contains erythrocytes, leukocytes, platelets.

Question 21

Explain the causes and symptoms of scurvy

Answer 21

Caused by vitamin C deficiency
Makes it so collagen fibers can’t form which weakens gums, teeth, bones, and internal mucosa
Wounds and fractures don’t heal well
Prevalent among PIRATES!!!

Question 22

Explain the causes and symptoms of marfan syndrome

Answer 22

Genetic disease on chromosome 15
Messes up your fibrillin, collagen and elastin which causes skeletal, vision, cardio, and connective abnormalities.
People who have it are usually tall and thin and usually die by age 50 due to heart weakness. Can bend joints abnormally.

Question 23

Explain the causes and symptoms of gangrene

Answer 23

When your tissue dies
Caused by lack of blood flow, injury, bacterial infection, or diabetes.
Dry(autoimmune or diabetes), wet(infection), gas(deep in the body and produces toxic gases).

Question 24

What is the structure, function, and location of areolar connective tissue?

Answer 24

◦Structure - Abundant ground substance, has scattered fibroblasts.
◦Function - Surrounds and protects tissues and organs
◦Location - Surrounds organs.

Question 25

What is the structure, function, and location of adipose connective tissue?

Answer 25

◦Structure - Closely packed adipocytes(fat cells).
◦Function - Store energy, protect, cushions, insulates.
◦Location - Subcutaneous layer, covers and surrounds some organs.

Question 26

What is the structure, function, and location of reticular connective tissue?

Answer 26

◦Structure - Gel-like ground substance. Has reticular fibers, fibroblasts, and leukocytes.
◦Function - Supportive framework for lymphatic organs and bone marrow.
◦Location - Lymphatic organs and bone marrow.
■Dense Connective Tissue Proper

Question 27

What is the structure, function, and location of dense regular connective tissue?

Answer 27

◦Structure - Gel-like ground substance. Has reticular fibers, fibroblasts, and leukocytes.
◦Function - Supportive framework for lymphatic organs and bone marrow.
◦Location - Lymphatic organs and bone marrow.
■Dense Connective Tissue Proper

Question 28

What is the structure, function, and location of dense irregular connective tissue?

Answer 28

◦Structure - Collagen fibers randomly arranged, sparse ground substance.
◦Function - withstands stresses in all directions.
◦Location - Dermis, periosteum.

Question 29

What is the structure, function, and location of elastic dense connective tissue?

Answer 29

◦Structure - Branching elastic fibers and some fibroblasts.
◦Function - Allows stretching of some organs.
◦Location - Walls of large elastic arteries and bronchial tubes.

Question 30

Describe (Structure, function, and location) the three loose connective tissue proper subtypes

Answer 30

Loose Connective Tissue (few fibers, more ground substance)
•Areolar Connective Tissue
S:abundant ground substance; gel like
F: surronds and protects tissues and organs; loosely binds epithelia to deeper tissue
L:Subcutaneous layer under skin; surrounds organs
•Adipose Connective Tissue
S: Closely picked adipocytes (fat cells); nucleus squeezed to one side by large fat drops
F: Stores energy; protects; cushions; and insulates
L: Subcutaneous layer; covers and surrounds some organs.
•Reticular Connective Tissue - Thin, webbed, branched fibers for strength.
S: Ground substance is gel like; scattered arrangement of fibers, fibroblasts, and leukocytes
F: Provides supportive framework for lymphatic organs and bone marrow
L: Lymphatic organs and bone marrow

Question 31

Describe (Structure, function, and location) the three dense connective tissue proper subtypes

Answer 31

Dense Connective Tissue (more fibers, less ground substance)
•Regular Connective Tissue
S: Densly packed; parallel collagen fibers; fibroblast between layer of fibers; scarce ground substance
F: Resists stress applied in one direction
L: Tendons and ligaments
•Irregular Connective Tissue
S: Collagen fibers randomly arranged and clumped together; fibroblasts amoung fibers; sparse ground substance
F: Withstands stresses in all directions
L: Dermis; periosteum covering bone;organ capsules
•Elastic Connective Tissue - Stretch and recoil.
S: Predominatly branching elastic fibers; fibroblasts occupy some spaces between fibers
F: Allows stretching of some organs
L: Walls of large elastic arteries and bronchial tubes