Week 3

Question 1

What is a tissue?

Answer 1

A tissue is made up of specialized groups of cells that coordinate together to perform the specific functions of that tissue.

Question 2

What are the four main types of tissues in the human body?

Answer 2

1. Epithelial Tissue (Integument)
2. Connective Tissue
3. Muscle Tissue
4. Neural Tissue

Question 3

What are the important functions of epithelial tissue?

Answer 3

1. Physical Protection – Protects against dehydration and chemicals.
2. Control Permeability – Semi-permeable (selective) and impermeable.
3. Sensory Stimuli – Sensory nerve supply including neuroepithelia.
4. Secretions – Glands that secrete mucous and fluids for protection and messaging.

Question 4

What are the key features of epithelial cells?

Answer 4

1. Apical Surface
2. Basolateral Surface
3. Cilia
4. Microvilli – Increase surface area for absorption.
5. Firm attachment to each other via junctions (e.g., gap junctions).
6. Endoplasmic Reticulum – Rough and smooth.

Question 5

How is epithelial tissue classified?

Answer 5

1. Shape:
   - Squamous
   - Cuboidal
   - Columnar
2. Number of Cell Layers:
   - Simple
   - Stratified

Question 6

What are the characteristics and locations of squamous epithelia?

Answer 6

• Simple Squamous: Delicate, smooth, for absorption or diffusion.
  Locations: Lungs, blood vessels (mesothelium, endothelium).
• Stratified Squamous: Multiple layers for mechanical stress.
  Locations: Mouth (non-keratinized), skin (keratinized).

Question 7

What are the characteristics and locations of cuboidal epithelia?

Answer 7

• Simple Cuboidal: Minimal protection.
  Locations: Kidney tubules.
• Stratified Cuboidal: Rare, found in ducts.
  Locations: Mammary gland ducts.
• Transitional Epithelium: Stretches and recoils.
  Locations: Urinary bladder lining.

Question 8

What are the characteristics and locations of columnar epithelia?

Answer 8

• Simple Columnar: For secretion and absorption.
  Location: Stomach.
• Pseudostratified Columnar: Single layer of cells with various types.
  Locations: Respiratory tract, male reproductive system.
• Stratified Columnar: Rare, provides protection.
  Locations: Anus, urethra.

Question 9

What are glands, and how are they classified?

Answer 9

Glands: Groups of epithelial cells that produce secretions.

Endocrine Glands: Release secretions (hormones) into the extracellular fluid. Ductless.
Example: Hormones.

Exocrine Glands: Release secretions onto an epithelial surface via ducts.
Example: Sweat glands, serous, mucous, mixed.

Question 10

Distinguish between simple and stratified epithelial tissue

Answer 10

Simple epithelial tissue has a single layer of cells, while stratified epithelial tissue has multiple layers.

Question 11

Describe how structure relates to function and location of different types of epithelial tissue

Answer 11

• Squamous epithelium (simple and stratified) is designed for absorption and protection, found in regions with mechanical stress (e.g., skin and lungs).
• Cuboidal epithelium is designed for minimal protection and is found in the kidneys and ducts.
• Columnar epithelium is specialized for secretion and absorption and is found in organs like the stomach and respiratory tract.

Question 12

Define a gland and distinguish between endocrine and exocrine glands

Answer 12

• Gland: A group of epithelial cells that produce secretions.
• Endocrine Glands: Ductless, secrete hormones into the bloodstream.
• Exocrine Glands: Secrete substances onto epithelial surfaces via ducts (e.g., sweat glands).

Question 13

What are the general features of connective tissue?

Answer 13

1. Specialized Cells
2. Extracellular Protein Fibers and Ground Substance
3. Matrix – The material surrounding the cells.

Functions:
- Connects epithelial cells to the body.

• Structural framework, transport of fluids, protection of organs.
• Supports, surrounds, and connects tissues.
• Stores energy reserves (e.g., lipids).
• Defends against microbial invasion.

Question 14

What are the three main types of connective tissue?

Answer 14

1. Connective Tissue Proper
2. Fluid Connective Tissue
3. Supporting Connective Tissue

Question 15

What are the characteristics of connective tissue proper?

Answer 15

• Matrix and several cell types.
• Includes Loose Connective Tissue and Dense Connective Tissue.

Question 16

What are the types of loose connective tissue and their functions?

Answer 16

1. Adipose Tissue: Fat cells with little extracellular matrix. Stores fat for energy and provides insulation.
2. Reticular Tissue: Made up of a network of reticular fibers, providing a supportive framework for soft organs.

Question 17

What are the types of dense connective tissue and their functions?

Answer 17

1. Dense Regular Connective Tissue: Collagen fibers packed into parallel bundles for strength.
2. Dense Irregular Connective Tissue: Collagen fibers interwoven in a mesh-like network for flexibility and strength.

Question 18

What are the types of fluid connective tissue?

Answer 18

1. Blood: Plasma matrix containing erythrocytes, leukocytes, and platelets.
2. Lymph: Fluid matrix containing lymphocytes.

Question 19

What are the characteristics of supporting connective tissue?

Answer 19

Cartilage: Gel matrix with chondrocytes in lacunae.

Types:
1. Hyaline Cartilage: Tough and flexible.
2. Elastic Cartilage: Elastic fibers, very flexible (e.g., ear, larynx).
3. Fibrocartilage: Collagen fibers, very tough.

Bone: Matrix of calcium salts and collagen fibers. Contains osteocytes in lacunae, communicating through canaliculi.

Question 20

What is a membrane?

Answer 20

A membrane is a combination of epithelial and connective tissues that work together to protect organs and the body.

Question 21

What are the types of membranes and their characteristics?

Answer 21

1. Mucous Membranes: Line passageways, lubricate, protect, and aid in absorption or secretion.
2. Serous Membranes: Thin membranes around organs, attaching the organ to the body.

Examples: Pericardium, pleura, peritoneum.

Two surfaces: Parietal (lining cavity) and visceral (lining organ).

3. Cutaneous Membranes: Skin; thick, waterproof, and dry.
4. Synovial Membranes: Line joints, produce synovial fluid for lubrication.

Question 22

What are the characteristics of synovial epithelia?

Answer 22

1. Develops within connective tissue.
2. No basal lamina.
3. Contains gaps.
4. Allows continuous exchange between synovial fluid, capillaries, and connective tissue.

Question 23

Describe the general features of connective tissue

Answer 23

Connective tissue is made of specialized cells, extracellular protein fibers, and ground substance that form a matrix. It connects, supports, surrounds, and protects various tissues in the body, stores energy, and defends against microbial invasion

Question 24

Describe the basic composition and purpose of extracellular fluid

Answer 24

Extracellular fluid includes blood plasma, lymph, and tissue fluid. It serves to transport nutrients, waste products, and gases and helps maintain a stable internal environment.

Question 26

Describe the characteristics that distinguish connective tissue proper, fluid connective tissue, and supporting connective tissue

Answer 26

Connective Tissue Proper: Includes loose and dense connective tissues. Fluid Connective Tissue: Includes blood and lymph. Supporting Connective Tissue: Includes cartilage and bone.

Question 27

Define a membrane and list the structural and functional characteristics of serous, mucous, cutaneous, and synovial membranes

Answer 27

Membrane: A combination of epithelial and connective tissues that protect organs. Mucous Membranes: Line passages and aid in absorption/secretion. Serous Membranes: Surround organs, with parietal and visceral surfaces. Cutaneous Membranes: Skin, waterproof and dry. Synovial Membranes: In joints, produce synovial fluid for lubrication.

Question 28

What is the structure of skeletal muscle tissue?

Answer 28

Fiber Shape: Long, cylindrical. Nuclei: Multinucleate (multiple nuclei per fiber), nuclei located peripherally. Striations: Present (due to the organized arrangement of actin and myosin). Other Features: Cannot divide, but contains satellite cells (stem cells) for limited regeneration.

Question 29

What is the function of skeletal muscle tissue?

Answer 29

Voluntary Movement: Responsible for locomotion, facial expressions, posture, and other voluntary movements. Heat Production: Generates heat as a by-product, contributing to thermal homeostasis. Location: Attached to bones and around entrance points to the body (e.g., mouth, anus).

Question 30

What is the structure of cardiac muscle tissue?

Answer 30

- Fiber Shape: Short, branched fibers. - Nuclei: Typically one nucleus, but can have up to five. - Striations: Present (similar to skeletal muscle). - Intercalated Discs: Specialized junctions that interlock cell membranes, allowing synchronized contractions.

Question 31

What is the function of cardiac muscle tissue?

Answer 31

Involuntary Movement: Contracts to pump blood through the heart and circulatory system. Intrinsic Rhythm: Contracts on its own rhythm, controlled by pacemaker cells, without external stimulation. Location: Found in the heart (cardiomyocytes).

Question 32

What is the structure of smooth muscle tissue?

Answer 32

Fiber Shape: Spindle-shaped cells. Nuclei: Single nucleus per fiber, centrally located. Striations: None (non-striated muscle). Regeneration: Can regenerate (has higher regenerative capacity compared to skeletal and cardiac muscles).

Question 33

What is the function of smooth muscle tissue?

Answer 33

Involuntary Movement: Responsible for involuntary movements such as digestion, secretion, blood flow, and contraction of airways. Location: Found in the walls of major organs and passageways (e.g., digestive, urinary, and reproductive systems, airways, and arteries).

Question 34

Describe the structure and function of skeletal muscle tissue, cardiac muscle tissue, and smooth muscle tissue.

Answer 34

Skeletal Muscle Tissue: Structure: Long cylindrical fibres, multinucleate, striated, no regenerative ability (except for satellite cells). Function: Voluntary movement, heat production, and supporting body movements. Location: Attached to bones and around body entrances (e.g., mouth, anus). Cardiac Muscle Tissue: Structure: Short, branched fibres, one or more nuclei, striated, intercalated discs. Function: Involuntary contraction to pump blood, intrinsic rhythm controlled by pacemaker cells. Location: Found in the heart (cardiomyocytes). Smooth Muscle Tissue: Structure: Spindle-shaped fibers, single centrally located nucleus, non-striated, regenerative. Function: Involuntary control of movement in internal organs, regulation of blood flow, digestion, and respiration. Location: Walls of major organs and passageways (e.g., digestive, urinary, and reproductive systems).

Question 35

What is the structure of a multipolar neuron?

Answer 35

Cell Body: Contains the nucleus and other organelles, responsible for metabolic activities. Axon: Transmits electrical signals (action potentials) to other cells (e.g., other neurons, muscles, glands). Dendrites: Receive signals from other neurons, increasing the neuron's surface area for communication.

Question 36

What is the function of a multipolar neuron?

Answer 36

Transmission of Impulses: The axon transmits electrical signals to other cells, enabling communication within the nervous system. Information Reception: The dendrites receive signals from other neurons, integrating incoming information to determine the cell's response.

Question 37

What are neuroglia and what are their functions?

Answer 37

Neuroglia: Support cells that maintain homeostasis, provide protection, and supply nutrients to neurons. Astrocytes: Provide structural support, regulate blood-brain barrier, and maintain extracellular ion balance. Microglia: Act as the immune cells of the nervous system, removing waste and protecting against infection. Oligodendrocytes: Produce myelin in the central nervous system, insulating axons and speeding up electrical signal transmission.

Question 38

Describe the structure and function of the components within a multipolar neuron.

Answer 38

Structure: Cell Body: Contains the nucleus and organelles, responsible for neuron functions. Axon: Transmits electrical impulses to other neurons, muscles, or glands. Dendrites: Receive signals from other neurons. Function: Axon: Transmits action potentials to communicate with other cells. Dendrites: Receive incoming signals from other neurons, integrating information.

Question 39

Describe the function of the various neuroglial cells (i.e., astrocytes, microglia, and oligodendrocytes).

Answer 39

Astrocytes: Provide support to neurons, regulate the blood-brain barrier, and maintain ion balance in the extracellular environment. Microglia: Act as immune cells, cleaning up cellular debris, and protecting against infection in the nervous system. Oligodendrocytes: Produce myelin in the central nervous system, which insulates axons and increases the speed of electrical signal transmission.