Week 5 - Cells and Tissues

Question 1

Define Tissue

Answer 1

an organised aggregation of cells (and their products) that function collectively

Question 2

What are the four tissue types?

Answer 2

Epithelial, Connective, Muscular and Nervous

Question 3

Define epithelial tissue.

Answer 3

Sheets of cells that cover the exterior surfaces of the body, line internal cavities and passageways and form certain glands.

Question 4

Define connective tissue.

Answer 4

Bonds cells and organs of body together and functions in protection, support and integration of all parts of body.

Question 5

Define muscular tissue.

Answer 5

Is excitable, responds to stimuli and contracts to provide movement, has three major types (smooth, skeletal and cardiac).

Question 6

Define nervous tissue

Answer 6

Excitable, allows propagation of nerve impulses to allow communication between different regions of the body.

Question 7

What is a tissue membrane?

Answer 7

A thin layer of cells that cover the outside of the body, the organs, internal passageways that lead to exterior of body, and lining of moveable joint cavities.

Question 8

What are the two types of tissue membranes

Answer 8

Epithelial membranes and connective tissue membranes

Question 9

What is a serous membrane?

Answer 9

A type of epithelial membrane which is composed of mesothelioma (mesodermally derived epithelial tissue) supported by a layer of connective tissue.

Question 10

What is the cutaneous membrane?

Answer 10

The cutaneous membrane is the membrane which comprises the skin

Question 11

What is the structure and function of epithelial membranes?

Answer 11

Comprised of epithelium attached to a layer of connective tissue, the layer of the epithelial tissue line body cavities and hollow passageways that open into external environments. Covered by mucous secreted by epithelial exocrine glands.

Question 12

What are the six types of cell to cell junctions?

Answer 12

Gap, tight, hemidesmosomes, desmosomes, adherens, anchoring

Question 13

Describe tight junctions.

Answer 13

Interlocking membrane proteins fuse adjacent cells together, prevents the passage of water and solutes between cells
Eg/ epithelium lining intestinal tract

Question 14

Describe anchoring junctions

Answer 14

Contains plaque (layer of protein connecting membrane proteins to microfilaments of cytoskeleton), provide strong and flexible connections, resist separation during contractile activities, three types: desmosomes, hemidesmosomes and adherens

Question 15

Describe desmosomes

Answer 15

Occur in patches in membranes of cells, patches are made up of structural proteins on inner surface of cell membrane, cadherin (adhesion molecule) is embedded in patches and projects through cell membrane to link with other cadherin molecules of adjacent cells eg/ cardiac muscle

Question 16

Describe hemidesmosomes.

Answer 16

Link cells to extracellular matrix, contains adhesion protein integrins instead of cadherin, look like half a desmosome

Question 17

Describe Adherins.

Answer 17

Use integrins or cadherins depending on what they are linking to, junction characterised by presence of contractile protein actin located on cytoplasmic surface of cell membrane, actin can connect isolated patches or form belt like structure inside cell

Question 18

Describe Gap Junctions

Answer 18

Form intercellular passageways between membranes of adjacent cells to facilitate movement of small molecules and ions between cytoplasm of adjacent cells

Question 19

What are the functions of epithelial tissue?

Answer 19

Provide body with line of defence, allow selective control of materials across a physical barrier, secretion, sensation

Question 20

How is epithelial tissue classified?

Answer 20

By shape (squamous, columnar, and cuboidal), and by layers (simple, stratified and pseudostratified).

Question 21

What is the function of simple squamous epithelium and where can it be found?

Answer 21

Allows materials to pass through by diffusion and filtration and secretes lubricating substance. Located in air sacs of lungs, lining of heart, blood vessels and lymphatic vessels.

Question 22

What is the location and function of simple cuboidal epithelium?

Answer 22

Secretes and absorbs. Located in the ducts and secretory portion of small glands and in kidney tubules

Question 23

What is the location and function of Simple Columnar Epithelium?

Answer 23

Absorbs and also secretes mucous and enzymes. Cililated tissues located in: uterine tubes, bronchi and uterus. Non-Ciliated located in: digestive tract and bladder

Question 24

What is the location and function of pseudostratified columnar epithelium?

Answer 24

Secretes mucous, Ciliated tissue moves mucous. Ciliated tissue line trachea and much of upper respiratory tract.

Question 25

What is the location and function of stratified squamous epithelium?

Answer 25

Protects against abrasion, lines esophagus, mouth and vagina.

Question 26

What is the location and function of stratified cuboidal epithelium?

Answer 26

Protective tissue found in sweat gland, salivary glands and mammary glands

Question 27

What is the function and location of stratified columnar epithelium?

Answer 27

Secretes and protects. Found in male urethra and ducts of some glands

Question 28

What is the function and location of transitional epithelium?

Answer 28

Allows urinary organs to expand and stretch, lines the bladder, urthera and ureters.

Question 29

What is an exocrine gland?

Answer 29

A gland that releases its contents through a duct that leads to the epithelial surface

Question 30

Where are simple alveolar glands found?

Answer 30

Not found in adults, is a prerequisite of simple branched glands

Question 31

What is the purpose of simple branched alveolar?

Answer 31

Sebaceous (oil) glands

Question 33

Where are simple tubular ducts found?

Answer 33

Intestinal glands

Question 34

Where are simple coiled tubular glands found?

Answer 34

Merocrine sweat glands

Question 35

Where are simple branched tubular glands found?

Answer 35

Gastric and mucous glands of the esophagus, tongue and duodenum

Question 36

Where are compound alveolar ducts found?

Answer 36

Mammary glands.

Question 37

Where are compound tubuloalveolar ducts found?

Answer 37

Salivatory glands; glands of respiratory passages; and pancreas.

Question 38

Where are compound tubular ducts found?

Answer 38

Mucous glands (in mouth), bulbourethral glands (in male reproductive system), and testes (seminiferous tubules).

Question 39

What are the two categories of exocrine glands?

Answer 39

Unicellular or multicellular.

Question 40

What are the characteristics of unicellular exocrine glands?

Answer 40

Scattered single cells

Question 41

What are the characteristics of multicellular exocrine glands?

Answer 41

Serous glands develop from simple epithelium, line internal cavities, release secretions directly into cavities or through tubular ducts.

Question 42

Describe merocrine secretions.

Answer 42

Secretions are inclosed in vesicles that move to the apical surface of the cell, which is then released by exocytosis.

Question 43

Describe the process of Apocrine Secretion.

Answer 43

The secretion accumulates near the apical portion of cell, the apical portion of the cell and its contents are ‘pinched off’ and released. Little damage is done to cell.

Question 44

Describe the process of holocrine secretion.

Answer 44

Cell accumulates secretory products and releases them by rupturing and destroying the entire gland. Mature cell dies.

Question 45

What are the four kinds of membranes in the human body?

Answer 45

Mucous, serous, synovial and cutaneous.

Question 46

What is the function of mucous membranes?

Answer 46

Line passageways that communicate with the exterior, produces mucous.

Question 47

What is the function of serous membranes?

Answer 47

Line internal cavities that do not open to the outside, divided into parietal (inner surface of cavity) and visceral (lines outer surface of organ) portions, minimises friction between opposing parietal and visceral surfaces.

Question 48

What are the functions of synovial membranes?

Answer 48

Line joint cavities, secrete synovial fluid.

Question 49

What is the function of cutaneous membrane?

Answer 49

Covers the surface of the body creating a barrier, composed of two main layers (dermis and epidermis).

Question 50

What are the three groups of connective tissue?

Answer 50

Connective tissue proper, cartilage and bone.

Question 51

What are the 5 kinds of connective tissue proper?

Answer 51

1. Areolar tissue 2.White Fibrous Tissue 3.Yellow Fibrous Tissue 4.Mucous Tissue 5.Retiform Tissue

Question 52

Describe the structure and purpose of areolar tissue.

Answer 52

Tissue forms one unbroken membrane compared of interlacing white and yellow elastic fibres variously superimposed. Main function is to bind parts together

Question 53

What are the three types of cells found in areolar tissue?

Answer 53

Flattened lamellar cells, granule cells, and plasma cells of Waldeyer

Question 54

Describe the structure and function of white fibrous tissue.

Answer 54

In form of ligaments it binds bones together, in form of tendons it binds muscles to bones or other structures, and it protects organs. White elastic fibres dominate the matrix, not elastic. In tendons and ligaments fibre bundles run parallel to each other.

Question 55

What is the structure and function of yellow elastic tissue?

Answer 55

Yellow elastic tissue has a greater elastic property. Primarily composed of elastin fibres.