TERM 1

Question 1

What are the four types of tissue

Answer 1

Epithelial
Connective
Muscles
Nervous

Question 2

What are the three components of tissue

Answer 2

cells, extracellular matrix, tissue fluid

Question 3

What is muscle tissue

Answer 3

contractile (it contracts - Muscle tissue can shorten lengths and close down spaces). The cytoplasm of muscle cells are packed with contractile apparatus. It consists of long thin cells.

Question 4

What are the three types of muscle

Answer 4

Skeletal (striated, highly organized arrangement of contractile proteins)
Smooth (Non – striated and (smooth) randomly ordered arrangement of contractile proteins)
Cardiac (striated, less highly ordered arrangement of contractile proteins) muscle. This can be found in the heart.

Question 5

What is nervous tissue

Answer 5

Nervous tissue is used for communication. Nervous tissue receives, generates and transmits electrical signals.
The cells in nervous tissue are called neurons. There are also support cells in nervous tissue. Nerve cells have different parts cell body (soma), dendrites, axon, and terminals.

Question 6

What is epithelial tissue

Answer 6

Epithelial tissue covers surfaces, separates compartments within the body. It contain cells that are connected, the cells define the function of the tissue.
Epitherlial tissue has good regenerative power i.e. after skin is cut and good adaptive power. Epithelial tissue can be very thick or thin to protect itself from harm or allow diffusion through it.
Epithelial tissue maintains coverage by forming cell to cell junctions to keep the cell close to each other. They also forms junctions with the extracellular matrix to keep tissue tightly in place and don’t have any contact inhibition (i.e. it doesn’t stop dividing when its touching lots of other cells).

Question 7

What are the different types of cell to cell junction?

Answer 7

1. Tight junctions (occluding junctions). There function is to seals intercellular spaces.
2. Gap junctions (communicating junctions; nexus) . There function is to provide cell to cell communication.
3. Desmosomes (adhering junctions; macula adherens). There function is to create a firm anchorage.
   All epithelial tissue lie on a basement membrane (basal lamina). The epithelial tissue connects to the basement membrane by half desmosomes (Hemidesmosomes) creating a very firm hold.

Question 8

How can epithelial tissue be classified?

Answer 8

There are three types of simple epithelial tissue 
Squamous – flat 
Cuboidal  - cuboid shape 
Columnar 
Pseudostratified columnar epithelium

There are three types of stratified epithelial tissue
Squamous – top layer is flat
Cuboidal - cuboid shape
Columnar
Transitional – only found in the urinal system

Question 9

What is the secondary functions of the epithelial?

Answer 9

Epithelial tissue has a large variety of secondary functions for example is in the trachea epithelial cells have finger like projections called cilia that help to move unwanted particles away from the lungs. Or in the GI tract they have villi and microvilli to help absorb food molecules. Another example is glands.

Question 10

What are glands?

Answer 10

Glands are collections of secretory epithelial cells (mostly). Glands can be single celled or multicellular. Glands can be exocrine where they secrete into tubes or endocrine where they secrete into blood.
Exocrine remains connected to the surface
Endocrine gland cuts off from the surface

Question 11

What are the different shapes of glands?

Answer 11

Glands can have different shapes:
Simple Tubular 
Simple Acinar 
Compound Tubular 
Compound Acinar 
Compound tubuloachinar

Question 12

What are different methods of secreting ?

Answer 12

Merocrine glands. The gland remains intact but little vesicles of the substance gets secreted out into the lumen. Most exocrine glands secrete this way. i.e. Thyroid gland

Apocrine glands. Secretion gets pinched off at the apex (top) of the cell (with a portion of the cell) and the portion of the cell and secretion are released together into the lumen. i.e. Sweat glands

Holocrine glands. The whole gland disintegrates with the secretion. The whole gland then regenerates. i.e. hair follicles

Question 13

Examples of endocrine glands

Answer 13

proteinaceous secretion

Pancreas

Question 14

Examples of exocrine glands

Answer 14

Mucous glands are a type of exocrine gland. They secrete proteoglycans which when mixed with water becomes mucus. E.g. mucous glands of the trachea and gut.

Serous glands are another type of exocrine gland. They have watery enzyme secretions that are rich in protein. E.g. exocrine pancreas.

Myoepithelial cells are muscle type cells that help the gland to get the secretion from the acini (a small saclike cavity in a gland, surrounded by secretory cells ) into the lumen.

Question 15

What is connective tissue?

Answer 15

Connective tissue connects and supports. It can be loose and or rigid. Lots of types of connective tissue (even more than epithelial tissue) These include bone, bone marrow, cartilage and adipose tissue.
Connective tissue has an extracellular matrix and tissue fluid as well as cells. The matrix and fluid defines structure and function (not the cells). Connective tissue has much fewer cells than epithelial tissue.

Question 16

Part of the extracellular matrix of connective tissue

Answer 16

The extracellular matric is made of up of three parts.
Fibres which are ‘rope-like’. The fibers are made of collagen (mainly a type of collagen called reticulin) and elastin.
A gound substance which is ‘jelly-like’
And tissue fluid which is a liquid

Question 17

Describe the fibres of the connective tissue

Answer 17

There are collagen and elastic fibres.
Collagen is inelastic but flexible with great tensile strength (doesn’t beak under tension). There are more than 19 different types. Tendons are a type of collagen which is known as Type I. Reticulin is known as type III and type IV is in basal lamina (non-fibrous). Cells called fibroblasts make up collagen. When many collagen fibrils come together, they form collagen fibre.
Elastic fibers consist of a protein called elastin and can stretch 1.5 times there resting length before returning to their ordinal shape. They consists of microfibriles and amorphours components and are found in sheets rather than in fibers. They also tend to be yellow.

Question 18

Describe the ground substance of the connective tissue

Answer 18

The ground substance is a semi solid gel. It consists of proteoglycans (meaning a protein connected to a carbohydrate) i.e. hyaluronic acid and glycoproteins (a carbohydrate connected to a protein)
The difference is that a proteoglycan is more carbohydrate with some protein while a glycoprotein is more protein with a carbohydrate attached.

Question 19

types of connective tissue

Answer 19

Loose: There are some types of cells you find permanently in loose connective tissue. For example: fibroblasts, macrophages, adipocytes, mast cells and undifferentiated mesenchyme cells. There are also some cells that are transient (only lasting a short period of time)for example white blood cells. You can find loose connective tissue around organs and blood vessels.
An example of dense regular tissue is a tendon. The dense regular tissue needs to be strong, and it all moves in the same direction. You can find dense regular tissue in muscles, tendons and ligaments.
An example of a dense irregular connective tissue is the dermis of the skin. Dense irregular tissue needs to be more flexible and more in more than one direction. You can find dense irregular in the dermis of the skin and in the fibrous capsules of the joints.

Question 20

Conditions involving connective tissue

Answer 20

1. Leukaemia. Cancer of the blood or bone marrow.
2. Epidermolysis bullosa loss or abnormal fibers in the loose or dense connective tissue.
3. Tears in the Cartlidge
4. Osteoporosis/petrosis. Weakness of the bones