Histological anatomy: cells and tissues

Question 1

Outline the levels of organisation in the human body

Answer 1

chemical level (atoms and molecules) > cellular level (cells) > tissue level (e.g. epithelial tissue) > organ level (e.g. small intestine) > organ system level (e.g. digestive system) > organismal level (e.g. human)

Question 2

What are the 4 types of tissue?

Answer 2

1. Epithelial tissue
2. Connective tissue
3. Muscle tissue
4. Nervous tissue

Question 3

Describe Epithelial Tissue

Answer 3

• covers the external surface of the body
• lines cavities
• forms glands

Question 4

Describe the functions of epithelial tissue:

Answer 4

1. physical protection
2. Regulate the movement of substances into and out of the body
3. Secretions: some exocrine epithelial tissues produce secretions (hormones)
4. Sensory perception: richly innervated (e.g. touch receptors)

Question 5

Describe Connective Tissue

Answer 5

• cells are conspicuously separated

- the intervening spaces are filled with extracellular matrix

Question 6

Describe the functions of connective tissue:

Answer 6

• protection
• binding
• supports organs (structurally and functionally)

Question 7

Describe the extracellular matrix

Answer 7

= protein fibres and ground substance
Where:
protein fibres = collagen, elastic fibres, reticular fibres
ground substances = mixture of proteins, carbohydrates, salts and water (ground substance is watery, gel-like, semi-solid)

Question 8

List the 3 types of connective tissue protein fibres and briefly describe them

Answer 8

1. Collagen: most abundant, high tensile strength, flexible, long and unbranching
2. Elastic: 3D branching pattern, wavy, stretch then return to shape
3. Reticular: thin fibres, branching, interwoven, structural framework

Question 9

What are the 3 types of muscle tissue?

Answer 9

1. Skeletal
2. Cardiac
3. Smooth

Question 10

Describe some properties of a muscle tissue:

Answer 10

1. excitable
2. contractile
3. elastic
4. extensible

Question 11

Describe structure of a muscle cell:

Answer 11

• myofilaments
• myofibrils (structural bundles of myofilaments)
• muscle cell (fibre)
• myofilaments: protein filaments within the cell, thin (actin) and thick (myosin) filaments, aligned contractile units that function to produce mechanical work

Question 12

Describe striated vs. non-striated

Answer 12

Striated: result from the overlapping arrangement of parallel thick and thin filaments –> occurs in skeletal and cardiac muscle
Non-striated: smooth muscle

Question 13

List the 2 types of neural tissue cells

Answer 13

1. Neurons

2. Glial cells

Question 14

Describe neurons:

Answer 14

• perform communication, processing and control functions
• excitable
• high metabolic rate
• longevity
• non miotic

Question 15

Describe glial cells:

Answer 15

• supporting cells
• lots more glial cells then neurons
• do not propagate action potentials
• maintain and support neurons

Question 16

List the 8 types of epithelial tissue

Answer 16

1. Simple squamous epithelium
2. Simple cuboidal epithelium
3. Simple columnar epithelium
4. Pseudostratified columnar epithelium
5. Stratified squamous epithelium
6. Stratified cuboidal squamous
7. Stratified columnar epithelium
8. Transitional epithelium

Question 17

List some key terms of the 8 types of epithelial tissue

Answer 17

Simple columnar = a columnar epithelium that is unilayered
pseudo stratified epithelium = a type of epithelium that, although comprises of only a single layer of cells, has its cell nuclei positioned in a manner suggestive of stratified epithelia
squamous = flattened and scale - like
cuboidal = resembling a cube
keratinised = to produce or become like keratin
columnar = having the shape of a column