Histology

Question 1

what is histology?

Answer 1

• study of tissues

- 4 major tissues: epithelial, CT, muscular, nervous

Question 2

epithelial tissue

Answer 2

• lines all body surfaces + cavities
• avascular (lacks blood vessels)
• tight junctions
  functions: protection (stratified squamous), secretion (glandular), control of permeability (simple)

Question 3

epithelial tissue: cell layers

Answer 3

simple: single layer, sits on basement membrane
stratified: several layer, bottom most sits on basement
pseudostratified: stretched single layer, sit on basement membrane

Question 4

epithelial tissue: cell shape

Answer 4

cuboidal: specialized for secretion + absorption
columnar: secretion + absorption
squamous: irregular shaped (found on outer skin)
transitional: stratified cell but varies with stretch

Question 5

glandular epithelium

Answer 5

• subtype of epithelial tissue
• adapted for secretion
• consists of exocrine + endocrine glands

Question 6

glandular epithelium: exocrine glands

Answer 6

• secrete products on/in cavity

single celled: secrete mucous in digestive, urinary, reproductive + respiratory tract

multi-cellular: have ducts + passage ways (sudoriferous, sebaceous, salivary)

Question 7

glandular epithelium: endocrine glands

Answer 7

• ductless

- secrete hormones into blood

Question 8

connective tissue

Answer 8

• cells are separated by a matrix
  blasts: form + secrete matrix
  cytes: maintain matrix
  clasts: breakdown matrix

Question 9

connective tissue characteristics

Answer 9

• highly vascular
• lots of extracellular matrix
• function: support and connect tissues

Question 10

matrix

Answer 10

• extracellular (surrounds cells)
  1) protein fibers: collagen (strength), elastin (stretch + recoil)
  2) ground substances: unstructured material located b/w cells
  3) water

Question 11

types of connective tissue

Answer 11

connective tissue proper: loose (areolar, adipose), dense (regular, irregular)

adipose CT: - adipocytes (large + store triglyceride)

                 - highly vascular (metabolism)
                 - little matrix
                 - functions: shock absorption, insulate, store energy

Question 12

dense regular

Answer 12

• cells=fibroblasts
• little ground substance
• collagen fibers run in same direction
• forms tendons

Question 13

dense irregular

Answer 13

• cells=fibroblasts
• little matrix
• collagen fibers run in diff. directions
• allows for stretch

Question 14

bone

Answer 14

• spongy/compact
• cells=osteocytes (in lacunae)
• matrix (dense collagen fibers, hydroxyapatite crystals)
• highly vascular

Question 15

cartilage

Answer 15

• cells=chondrocytes (in lacunae)
• firm matrix (tight collagen fibers)
• avascular
• ground substance=chondroitin sulfate + hyaluronic acid

Question 16

blood

Answer 16

• RBC and WBC

- matrix is plasma

Question 17

histology major junctions

Answer 17

3 membrane junctions:

1) tight tissue: prevent substances b/w cells (molecules fused together)
2) desmosomes: loose, use linker attachments (allows flexibility)
3) gap: connected adjacent cells, allows communication (smooth + cardiac muscles)

Question 18

muscle types

Answer 18

skeletal: striated, voluntary movement
cardiac: striated, involuntary
smooth: non-striated, stretched area, involuntary

Question 19

nervous tissue

Answer 19

neurons: conduct electrical impulses

glial cells: surround + protect neurons

Question 20

membranes

Answer 20

• 2 or more tissues (simple organs)

- continuous multi-cellular sheets

Question 21

membrane types

Answer 21

1) mucous: mucosa
2) serous: serosa
3) cutaneous: skin

Question 22

mucous membranes

Answer 22

• line cavities leading out of the body
• epithelial layer (squamous/pseudostratified)
• areolar
• lamina proper

Question 23

serous membrane

Answer 23

• lines cavities that do not lead out
• covers organs in cavities
• visceral layer (organs), parietal layer (wall)

pleura: lungs [v: lung surface / p: thoracic wall]
pericardium: heart [v: heart surface / p: mediastinum]
peritoneum: abdominal cavity + viscera