Histology

What’s the organization of living matter

chemistry of life → cells → tissues → organs → organ systems → organism

What are the five principle tissues?

epithelial, connective and supporting, muscular, nervous, and hematolymphoid

what basic tissue is this

epithelial tissue

• nothing but tightly packed cells (no fibers)

• avascular

• found on surfaces

• PEAS (protection, excretion, absorption, secretion)

what basic tissue is this

connective and supporting tissue

• not as tightly packed as epithelial

• cells, ground substance, and extracellular fibers

• highly vascular

what basic tissue is this

hematolymphoid

• the blood and lymph of your body (the fluid)

  • ex. red blood cells, white blood cells, plasma, etc.

what basic tissue is this?

muscle tissue

• made up of muscle fibers and proteins for contraction

what basic tissue is this

nervous tissue

• communicative + control tissue

what is the layer between epithelial and connective tissue that connects the two together for vascular support?

basement membrane (basil lamina)

simple squamous epithelium

Structure - one layer of randomly shaped cells

Distribution

• Endothelium - lines blood/lymphatic vessels

• Mesothelium - lines body cavities

  • ex. around the lungs, heart, and abdomen

Function - helps reduce friction; E, A, S

simple cuboidal epithelium

Structure - one layer of cube shaped cells

Distribution - the inner lining of glands

Function - E, A, S

simple columnar epithelium

Structure - one layer of column shaped cells (nonciliated)

Distribution - inside lining of the digestive system

Function - E, A, S

pseudostratified columnar epithelium

Structure - one layer of column shaped cells (ciliated)

Distribution - found in respiratory system

Function - movement of mucus; P, E

stratified squamous epithelium

Structure

• Nonkeratinized - no layer of dead squamous cells

• Keratinized - layer of dead squamous cells

Distribution

• surface layer of skin (keratinized)

• inside nose, eyes, mouth, anus, ears, etc. (nonkeratinized)

Function - P, S

stratified cuboidal epithelium

Structure - multilayered cube shaped cells

Distribution - X

Function - P

stratified columnar epithelium

Structure - multilayered column shaped (ciliated or nonciliated)

Distribution - X

Function - P

urothelium (transitional epithelium)

Structure

• Empty - not as compacted as when the organ that it lines is empty

• Full (distended) - when the organ it lines is ful

Distribution - urinary system (ex. bladder)

Function - must always be stratifies for protection from all of the nasty stuff being filtered in the urinary system

what are the three basic types of connective and supporting tissues?

1. general (soft) connective tissues - connective tissue proper, reticular tissue, and adipose tissue

2. cartilage tissue

3. bone tissue

what differentiates connective tissues from epithelial tissues?

connective tissues have an extracellular matrix that is made primarily of water (ground substance), but also has fibers floating around

what are the fixed/resident cells found in connective tissues?

mesenchymals, fibroblasts/cytes, and adipocytes

what cell is this and where is it found

mesenchymal; is a resident/fixed cell found in connective tissue

what cell is this and where is it found

fibroblast/fibrocyte; a resident/fixed cell found in connective tissue; they create fibers and secrete them into extracellular surroundings

what cell is this and where is it found

adipose; is a resident/fixed cell found in connective tissue

identify all of the wandering/migrant cells that can be found in connective tissue

• macrophage

• mastocytes

• lymphocytes

• plasmocytes

what is good at resisting tension, but not compression?

collagen fibers

what is good at recoiling to its original shape?

elastic fibers

reticular vs. elastic vs. collagen fibers

elastic fibers are flexible, reticular fibers are flexible and more delicate, and collagen fibers are strong

what are the types of connective tissue proper

loose connective tissue, dense irregular connective tissue, dense regular connective tissue, and elastic tissue

what tissue is this

loose connective tissue (interchangeable with adipose tissue)

Structure - more spread out fibers pointing all different ways

Distribution- everywhere

Function - general glue; fexibility

what tissue is this

dense irregular connective tissue

Structure: dense mesh of fibers going in all directions

Distribution: the dermis, fascia around muscles, periosteum, submucosa of digestional tract, etc.

Function: great at resisting tension in all directions

what tissue is this

dense regular connective tissue

Structure - tightly packed, parallel collagen fibers

Distribution - tendons, ligaments, aponeuroses

Function - good at resisting tension in one direction

what tissue is this

elastic connective tissue

Structure - long, thin, branching fibers

Distribution - the wall of major arteries (ex. aorta, lungs, trachea, etc.)

Function - good at recoiling/regaining its original shape

what tissue is this

reticular tissue

Structure - looks like a net

Distribution - lymph nodes

Function - sturctural support for soft organs; maintains shape while being flexible

what tissue is this

Structure - interchangeable with loose connective tissues; globular cells

Distribution - underneath the skin; around organs; potentially everywhere

Function - energy storage