4. Basic Tissues

Question 1

What are the 4 Basic Tissues

Answer 1

• Epithelia
  
  • Connective Tissue
  • Muscle
  • Nervous

Question 2

Epithelium location

Answer 2

• Cover surfaces
  
  • Line cavities and tubes
  • Form glands

Question 3

Function of epithelial tissue

Answer 3

• Provide physical protection.
• Control permeability
• Provide sensation
• Produce specialised secretions

Question 4

Important characteristics of Epihelium

Answer 4

• Attachment - held onto basement membrane
• Avascularity - no blood vessels with the cells
• Regeneration - lost cells are quickly replaced by mitosis
• Polarity (apical and basal)
• Cellularity - cells separated by minimal amounts of ECM

Question 5

6 main types of epithelium

Answer 5

• Simple squamous
• Keratinised stratified squamous
• Non keratinised stratified squamous
• Simple cuboidal
• Simple columnar
• Pseudostratified stratified columnar with goblet cells

Question 6

Describe Simple Squamous Epithelium

Answer 6

• Flat cells - oval shaped nuclei
• One layer of cells

Major function - exchange of nutrients and gases

Location – blood vessels, alveoli

Question 7

Describe Simple Cuboidal Epithelium

Answer 7

• Square cells with round nuclei
• One layer

Major function – secretion and absorption

Location – glands, kidney tubules

Question 8

Describe Simple Columnar Epithelium

Answer 8

• Tall cells with oval, basally located nuclei
• One layer

Major function – absorption and secretion

Location – gastrointestinal tract

Surface modifications - microvilli

Question 9

Describe Keratinised Stratified Squamous Epithelium

Answer 9

• Flat surface cells with oval shaped nuclei
• Many layers
• Keratin

Major function – protection, barrier (waterproof)

Location – skin, gums

Question 10

Describe Non-Keratinised Stratified Squamous Epithelium

Answer 10

• Flat surface cells with oval shaped nuclei
• Many layers

Major function – protection, barrier

Location – oral cavity, oesophagus

Question 11

Describe Pseudostratified Ciliated Columnar Epithelium with Goblet Cells

Answer 11

• Tall cells
• Appears stratified as some cells don’t reach free surface.
• All cells touch basement membrane

Modifications – cilia & goblet cells

Functions – mucociliary escalator

Location - trachea and large respiratory airways

Question 12

What is an Intracellular junction?

Answer 12

Specialised area of cell membrane that bind one cell to another.

Question 13

Describe the 4 Intracellular Junctions. What are their functions?

Answer 13

Tight Junctions

- Interlocking proteins tightly bind cells together near apical edge 
- Prevent passage of water and solutes between cells – (e.g. in digestive tract) 

Desmosomes

- Very strong connections between adjacent cells 
- Proteoglycan arranged on the side of epithelial cells to bind them together
- Resist stretching and twisting 

Gap Junctions

- Cells held together by an interlocking membrane proteins containing a central pore 
- Connexons - Proteins that link two epithelial cells in a gap junction
- Allows movement of small molecules and ions between cells - found in cardiac muscle 

Hemidesmosomes

- Attach cells to the basement membrane
- Stabilise the position and anchor cell to the underlying tissue

Question 14

Define Connective Tissue

Answer 14

Consists of cells suspended within a uniform extracellular matrix.
Fills internal spaces, provides structural support for other tissues, transports materials within the body, and stores energy

Question 15

Functions of Connective Tissue

Answer 15

• Forms a structural framework for the body
• Supports, surrounds and interconnects other tissue types
• Protects delicate organs
• Transports fluids and dissolved materials
• Stores energy reserves
• Defends body from microorganisms

Question 16

3 specialised connective tissues

Answer 16

Blood, Bone, Cartilage

Question 17

What is Connective Tissue Proper?

Answer 17

Protective ‘packaging’ between tissues/organs.

Classified according to the type, arrangement and abundance of fibres, cells and ground substance.

Question 18

3 Types of Connective Tissue Proper

Answer 18

Loose (Areolar) Connective Tissue

Dense Irregular Connective Tissue

Dense Regular Connective Tissue

Question 19

What is Loose (Areolar) Connective Tissue

Answer 19

Found under the epithelium that covers and lines the body surfaces

Connects epithelial tissue to underlying tissues.

Hold some internal organs in place in the body cavity

Contains
	- Lots of ground substance
	- few fibres (collagen & elastic)
	- Variety of cells; 
		○ Fibroblasts
		○ Adipocytes
		○ Macrophages (transient)

Question 20

What is Dense Irregular Connective Tissue

Answer 20

Found in the dermis

Resists excessive stretching and distension

Fat tissue - energy stockpile for the body

Contains

- little ground substance 
- many collagen fibre bundles arranged haphazardly 
- few cells (mainly fibroblasts)

Question 21

What is Dense Regular Connective Tissue

Answer 21

Found in tendons and ligaments

Attaches muscles to bone in the form of tendons. And attached bone to bone in the form of ligaments.

Contains

- little ground substance 
- many densely packed bundles of collagen fibres arranged in parallel rows 
- few cells (mainly fibroblasts)

Question 22

3 Types of Muscle Tissue

Answer 22

Skeletal
Smooth
Cardiac

Question 23

Similarities between all muscle tissues

Answer 23

1. Elongated parallel to axis of contraction
2. Numerous mitochondria
3. Contractile elements

Question 24

Describe Skeletal Muscle and its function

Answer 24

• Long, Linear, cylindrical cells Striated (striped)
• Multinucleated
• Innervated by somatic nervous system

Function
- Moves and stabilises the skeleton 
- Forms sphincters in digestive and urinary tracts 
- Involved in respiration 
Attached to bone by tendons

Question 25

Describe Smooth Muscle and its function

Answer 25

- Short, fusiform cells - Non-striated - Single, centrally located nucleus - Innervated by autonomic nervous system - Located in the walls of organs, blood vessels and airways Function - Gastrointestinal movement - Alters diameter of airways and blood vessels

Question 26

Describe Cardiac Muscle and its function

Answer 26

- Found in the heart wall - Branched muscle fibres Striated - 1-2 central nuclei - Intercalated discs - Innervated by the autonomic nervous system Function - Helps to circulate blood & to maintain blood pressure

Question 27

Describe Nervous Tissue

Answer 27

carries information from one part of the body to another in the form of electrical impulses.