Types of biological tissues

Question 1

What are the four types of biological tissues?

Answer 1

Epithelial
Connective
Muscle
Nervous

Question 2

What are the two types of epithelial tissue?

Answer 2

Proper and glandular epithelium

Question 3

Briefly describe proper epithelium

Answer 3

It covers and lines the inner and outer body

Question 4

Briefly describe glandular epithelium

Answer 4

It forms glands and secretes hormones, as well as other substances

Question 5

Where is epithelial tissue found?

Answer 5

• Interface between compartments
• Line / cover all body surfaces, cavities and tubes
• Glands

Question 6

Name three functions of epithelium

Answer 6

• Covering, lining and protecting surfaces
• Performing absorption
• Secretion

Question 7

What are the characteristics of epithelia?

Answer 7

–Specialised cell to cell junctions
–Polarised
–Basement membrane
–Avascular– rely on connective tissue

Question 8

What are the three types of epithelium cell types?

Answer 8

Squamous
Cuboidal
Columnar

Question 9

Squamous epithelium

Answer 9

Lining and diffusion
•Endothelium
•Blood vessels and lymph
•Mesothelium
•Body cavities linings

Question 10

Columnar epithelium

Answer 10

Much more active

Question 11

What are the three types of layers of epithelium?

Answer 11

Simple- one layer of cells
Stratified- multiple layers on top of each other
Pseudostratified- mostly just one layer. Cells with different shapes and sizes

Question 12

What is transitional epithelium?

Answer 12

Stratified epithelium that can accommodate stretching

Question 13

Type of epithelium required for selective diffusion?

Answer 13

These epithelia are usually simple squamous type, to provide the smallest barrier to diffusion.

Question 14

Type of epithelium required for absorption/secretion?

Answer 14

These epithelia are usually columnar, as the cells contain lots of ER and golgi, for secretion. They often have microvilli, to increase the surface area of the apical surface for absorption.

Question 15

Type of epithelium required for physical protection?

Answer 15

These epithelia are always stratified (many layers), and can sometimes be keratinised on its apical surface, as in skin. The keratin helps to waterproof the skin.

Question 16

Where do endocrine glands secrete into?

Answer 16

They secrete hormones into the blood or to nearby cells

Question 17

Where do exocrine glands secrete into?

Answer 17

They secrete into tubes/ducts that lead to the outside of the body

Question 18

What can secretory cells synthesise, store and release?

Answer 18

• Proteins-e.g. in the pancreas
• Lipids-e.g. adrenal, sebaceous glands
• Complex of carbohydrates and proteins-e.g. salivary glands
• All the above-e.g. lactating mammary glands

Question 19

Name the four types of connective tissue

Answer 19

Proper
Cartilage
Bone
Blood

Question 20

How is connective tissue different to the other types of tissue?

Answer 20

Connective tissue is manly constituted of extracellular matrix rather than cells.

Question 21

What are the three main components of connective tissue?

Answer 21

Three types of fibres (collagen, elastic, reticular)
Ground substance
Main featured cells

Question 22

Collagen fibres

Answer 22

Makes up 30% of the human body’s dry weight
At least 28 types exist in vertebrates.
Created by mainly fibroblast cells
It’s what gelatin is made out of

Question 23

Elastic fibres

Answer 23

Have a rubber-like quality
Made out of the protein Elastin
Found in skin, lungs and large blood vessel walls

Question 24

Reticular fibres

Answer 24

Also made of collagen
Found in long bones and immune tissue
Suspends growing erythrocytes and plasma cells from its network i.e. bone marrow, the spleen, lymph nodes
Therefore is supportive to areas with rapidly changing populations of proliferating cells

Question 25

What is ground substance?

Answer 25

Background around fibres and cells are located. The 'ground substance' of extracellular matrix is an amorphous gelatinous material. It is transparent, colourless, and fills the spaces between fibres and cells

Question 26

What does ground substance do?

Answer 26

These molecules are very good at absorbing water, rather like a sponge, such that 90% of the extracellular matrix is made up of water. Allows tissue to return to original shape when compressed or deformed.

Question 27

Name five types of cells in the extra-cellular matrix

Answer 27

``` Fibroblasts Macrophages Adipocytes Mast cells Stem cells ```

Question 28

Briefly describe fibroblasts

Answer 28

Fibroblasts secrete collagen and elastin. They are the least specialised of the connective tissue cells and can differentiate into other cell types found in the ECM. Fibroblasts are spindle shaped, and actively secreting matrix.

Question 29

Briefly describe macrophages

Answer 29

These are phagocytes -these cells 'eat' particles such as bacteria. These cells are derived from white blood cells called monocytes

Question 30

Briefly describe adipocytes

Answer 30

Adipocytes are fat cells. There are two types of fat cells: White Fat Cells, which are the most common type in adults. These are unilocular, have a large diameter, and are found in subcutaneous, omentum & mesentry regions. Brown Fat Cells are multilocular. They are smaller than white adipocytes. They are present in large amounts in the new-born & hibernating animals.

Question 31

Briefly describe mast cells

Answer 31

They are found close to small blood vessels in loose connective tissue. They contain large secretory granules of heparin proteoglycan-a weak anticoagulant. They also contain histamine, which promotes an inflammatory reaction when secreted

Question 32

Name the two subdvisions of connective tissue proper

Answer 32

Loose | Dense (regular/irregular)

Question 33

Briefly describe loose connective tissue

Answer 33

Little collagen Lots of ground substance Viscous and gel-like Inflammatory and immune reactions

Question 34

Briefly describe dense regular connective tissue

Answer 34

``` Ordered Densely packed Little ECM Parallel Maximum Strength ```

Question 35

Briefly describe dense irregular connective tissue

Answer 35

``` Mostly collagen Cells are sparse Fibroblast Strength Resistance to tearing and stretching ```

Question 36

Bone and cartilage are examples of what type of connective tissue?

Answer 36

Supporting connective tissue

Question 37

What are the three types of cartilage?

Answer 37

Hyaline: Most common -has a glassy appearance. Sparse collagen. Fibrocartilage: tendon insertions and invertebral discs: reinforced with parallel bundles of collagen fibres. The strongest. Elastic cartilage: external ear and epiglottis: flexible and resilient -has elastic fibres as well as collagen fibres.

Question 38

What are the four main qualities of muscle tissue?

Answer 38

Excitability-the ability to respond to stimuli Contractibility-the ability to contract-i.e. shorten Extensibility –the ability to stretch without tearing Elasticity-ability to return to original shape

Question 39

Name the three types of muscle tissue

Answer 39

Smooth muscle Cardiac muscle Skeletal muscle

Question 40

Describe smooth muscle tissue

Answer 40

Smooth muscle is unstriated, made of small fusiform cells closely packed together. Single nuclei that is centrally located. Found in the walls of hollow organs so sometimes known as visceral muscle. Under autonomic control

Question 41

Describe cardiac muscle tissue

Answer 41

Cardiac muscle is striated due to dense arrangements on actin and myosin, and is cylindrical It is autonomic control. It has a unique cell to cell junction known as intercalated disks Single nuclei, based in the centre.

Question 42

Describe skeletal muscle tissue

Answer 42

Skeletal muscle is a striated, cylindrical muscle under staining due to the dense arrangement of actin and myosin Each sketetal muscle cell is multinucleated due to being so large, pushed to the periphery It is under voluntary control –by general somatic efferent It attaches to bones via tendons, muscles have to traverse a joint in order to have any action.

Question 43

What are contractions caused by?

Answer 43

Interactions between myofilaments

Question 44

Give the steps required for contraction

Answer 44

Contraction requires ATP and calcium Sarcoplasmic reticulum stores calcium Action potential opens the calcium channels –calcium floods into the cell Calcium binds with troponin Deforms tropomyosin, meaning the myosin heads can bind to the newly revealed sites on troponin ATP --> ADP and P –releases energy Myosin head binds to actin

Question 45

What causes contraction to stop?

Answer 45

Calcium stops flooding the muscle fibre because the nerve impulse has stopped. This leads to calcium being depleted. Calcium also unbinds from troponin

Question 46

Define the term 'neuron'

Answer 46

Nerve cells that are specialised cells that conduct electrical impulses.

Question 47

Describe the basic structure of all neurons

Answer 47

Each neuron contains a nerve cell body. Branching off the nerve cell body are the dendrites, which act like tiny antennae picking up signals from other cells. At the opposite end of the nerve cell body is the axon. The axon is insulated by a myelin sheath.

Question 48

How do nerve impulses travel through neurons?

Answer 48

Nerve impulses are received by the dendrites, travel down the branches of the dendrites to the nerve cell body, and are carried along the axon.

Question 49

What is the ground substance in blood?

Answer 49

Blood plasma