Histology Topic 1: Introduction

Question 1

What is histology?

Answer 1

Histology is the study of tissues (aggregates of cells)

and cells at the microscopic level

Question 2

Why do tissues need to be prepared for viewing under a microscope?

Answer 2

Fresh tissue is non-permanent, sections are not thin

enough and lacks colour.

Question 3

What is the process of preparing tissue for microscope viewing?

Answer 3

>Fixation: Tissue is preserved 
>Processing: Water is removed and 
tissues are impregnated with wax—>to 
remove water, tissue must go through 
increasing strengths of Alcohol 
>dehydrated gradually to prevent 
shrinkage 
>Section Cutting: Thin section cut from 
paraffin embedded tissue—>ribbons of 
wax and tissue—>tissue placed on 
slide and wax then dissolved with a 
clearing agent
>Staining: Haematoxylin(stains nucleus 
blue to black colour) and Eosin(stains 
cytoplasm and intercellular components 
pink) added to see intracellular content
—>to make prominent the sample is 
dehydrated in absolute alcohol

Question 4

The highest surface area to volume ratio is found in which type of a cell? A larger or smaller cell?

Answer 4

Smaller cell

Question 5

What are the benefits of a higher SA to Volume ratio?

Answer 5

1. Larger surface area means more space for nutrients and other solutes to diffuse into the cell
2. Smaller volume relative to SA increases efficiency at which nutrients diffuse within a cell
3. This all equates to increased rate of diffusion

Question 6

What are the advantages of multicellularity?

Answer 6

1. Allows cell to exceed cell size limits (usually caused by diffusion)
2. Allows cell to have a longer lifespan
3. Allows for the occurrence of specialized tissues with specific functions
4. Allows for the production and repair of damaged cells

Question 7

Explain the hierachial organization of an organism

Answer 7

• Cells organized into tissues: groups of similar cells that work together on a specific task.
• Organs are structures made up of two or more tissues organized to carry out a particular function,
• Groups of organs with related functions make up the different organ systems

Question 8

What are the four primary types of tissue?

Answer 8

1. Epithelial Tissue
2. Connective Tissue
3. Muscle Tissue
4. Nerve Tissue

Question 9

What is the integumentary system and what is its function?

Answer 9

▪︎ hair, skin and nails
▪︎ Functions:
-encloses many internal structures of the body
- site for many sensory receptors

Question 10

What is the skeletal system and what is its function?

Answer 10

▪︎bones, cartilage and joints
▪︎Functions:
- supports the body
- enables movement alongside muscular system

Question 11

What is the muscular system and what is its function?

Answer 11

▪︎skeletal muscles and tendons
▪︎Functions:
-enables movement alongside skeletal system
- maintains body temperature

Question 12

What is the nervous system and what is its function?

Answer 12

▪︎Brain, Spinal cord and Peripheral nerves
▪︎Functions:
-detects and processes sensory information
-activates bodily responses

Question 13

What is the endocrine system and what is its function?

Answer 13

▪︎Pituitary gland, Thyroid gland, Pancreas, Adrenal gland, Testes/Ovaries
▪︎Functions:
-secretes hormones
-regulates bodily processes

Question 14

What is the circulatory system and what is its function?

Answer 14

▪︎Heart and Blood vessel
▪︎Functions:
- transport nutrients and oxygen to tissues
- equalizes body temperature

Question 15

What is the lymphatic system and what is its function?

Answer 15

▪︎Thymus, Lymph nodes, Spleen, Lymph vessels
▪︎Functions:
- returns fluid to the blood
-defends against pathogens

Question 16

What is the respiratory system and what is its function?

Answer 16

▪︎Nasal passage, Trachea, Lungs
▪︎Functions:
- to remove carbon dioxide from the body
- to deliver oxygen to the blood

Question 17

What is the digestive system and what is its function?

Answer 17

▪︎Stomach, Liver, Gall bladder, Small intestine, Large intestine
▪︎Functions:
- pro
cesses food for use by the body
- removes waste from undigested food

Question 18

What is the urinary system and what is its function?

Answer 18

▪︎Kidneys and Urinary bladder
▪︎Functions:
- controls water balance in the body
-removes waste from blood and excretes them

Question 19

What is the male reproductive system and what is its function?

Answer 19

▪︎Epididymis and Testes
▪︎Functions:
- produce several hormones and gametes
- deliver gametes to female gametes

Question 20

What is the female reproductive system and what is its function?

Answer 20

▪︎Mammary glands, Uterus and Ovaries
▪︎Functions:
-produces sex hormones and gametes
- supports embryo/foetus until birth
- produces milk for the infant

Question 21

What is the function of Tight Junctions and where are they found?

Answer 21

• Seal plasma membranes tightly together

* Digestive tract lining, bladder lining

Question 22

What is the function of Adhesion junctions/spot desmosomes and where are they found in the body?

Answer 22

• Permit some movement between cells
• Allow tissues to stretch and bend
• Skin

Question 23

What is the function of Gap junctions and where are they found in the body?

Answer 23

• Protein channels enable movement of materials between cells
• Liver, heart