Histology

Question 1

Describe eukaryotic cells?

Answer 1

-Outer membrane
-Inner cytosol – solution of proteins, electrolytes and carbohydrates
-Cytoskeleton – determines shape and fluidity of the cells
Made from thin, intermediate filaments and microtubules

Question 2

Describe the plasmalemma?

Answer 2

Separates cytoplasm from outside environment 
-Phospholipid bilayer (amphipathic) 
	Hydrophilic heads at outer and inner surfaces 
	Hydrophobic tails at centre 
-Contains integral proteins 
-Can exocytose and endocytose material 
-Fluid mosaic 
-Selectively permeable 
-Contains embedded cholesterol

Question 3

Describe the 3 components that make up to cytoskeleton?

Answer 3

• Microfilaments – 7nm – composed of actin
• Intermediate filaments - >10nm – composed of proteins
• Microtubules – 25nm – composed of tubulin
  Originate from organising centre called centrosome
  Dynein and kinesin attach and move along them

Question 4

Describe the nucleus?

Answer 4

Enclosed by nuclear envelope – inner and outer membrane with nuclear pores
Outer nuclear membrane studded with ribosomes
Contains chromosomes

Site of RNA synthesis – mRNA, tRNA in nucleus, rRNA in nucleolus

Question 5

Describe the role of the mitochondria?

Answer 5

generation of ATP and synthesis of certain lipids and proteins
- inner mitochondria is folded to form christae

Question 6

What are the roles of the smooth endoplasmic reticulum?

Answer 6

Continues processing of proteins from RER

Site of lipid synthesis

Question 7

What is the role of the rough endoplasmic reticulum?

Answer 7

Protein synthesis and initiation of glycoprotein formation

It is studded with ribosomes

Question 8

Describe the Golgi apparatus?

Answer 8

Composed of a group of flattened, membrane bound cisternae
Transport vesicles arrive at Golgi from SER
Modifies and packages macromolecules from SER

Question 9

What are the 3 types of intracellular junctions?

Answer 9

Occluding
Anchoring
Communicating

Question 10

Describe occluding/tight junctions?

Answer 10

link cells to form a diffusion barrier

Question 11

Describe anchoring junctions?

Answer 11

provide mechanical strength

sometimes called - Desmosomes

Question 12

Describe communicating/gap junctions?

Answer 12

allow selective diffusion between adjacent cells

Question 13

Describe phagocytosis?

Answer 13

Bacteria binds to cell surface, cell engulfs it to form phagosome, binds with lysosome containing digestive enzymes

Question 14

What is endocytosis?

Answer 14

Membrane invaginates, fuses and newly made endocytotic vesicle buds into cell

Question 15

What are the common acidic and basic dyes/stains?

Answer 15

haematoxylin – purple, basic dye

eosin – pink, acidic dye

Question 16

What are the 4 basic tissue types?

Answer 16

Epithelium
Connective tissue
Muscle
Nervous tissue

Question 17

Describe the basic epithelium?

Answer 17

Cover surfaces of body, line hollow organs, form glands

• All have basal lamina
• Non-vascular
• Usually polarised – apical and basal sides differ

Question 18

What are the functions of the epithelium?

Answer 18

o	Mechanical barrier
o	Chemical barrier 
o	Absorption 
o	Secretion 
o	Containment 
o	Locomotion

Question 19

How can epithelium be classified?

Answer 19

- Cell shape 
	Squamous – flattened 
	Cuboidal – cube 
	Columnar – tall and thin 
- Number of layers 
	Simple – one layer 
	Stratified – two or more layers 
	Pseudostratified – tissue appears to have multiple layers
- Cell surface, tissue surface specialisations 
	Prominent microvilli 
	Cilia 
	Keratinised 
- Presence of specialised cell types 
	Goblet cells

Question 20

Describe connective tissue?

Answer 20

Forms framework of body

dynamic role in development, growth and homeostasis of tissues, and energy storage (fat)

Question 21

Describe the 4 types of connective tissue?

Answer 21

Soft connective tissue - tendons, ligaments, mesentery, stroma of organs, dermis of skin
Loose
Dense regular if fibres aligned
Dense irregular if fibres run in many directions
Hard connective tissue - bone and cartilage
Strong, flexible, compressible, semi-rigid tissue
Blood and lymph

Question 22

Describe and name the 3 different types of cartilage?

Answer 22

Hyaline – articular surface, tracheal rings, costal cartilage, epiphyseal growth plates
Elastic
Fibrocartilage

Question 23

Describe the names of bone landmarks?

Answer 23

Outer shell of cortical bone makes up shaft – diaphysis Cancellous/trabecular bone occupies ends – epiphyses

Question 24

Describe Muscle tissue?

Answer 24

Specialised to generate force by contraction
Force is movement of actin fibres over myosin fibres
3 types
Smooth – involuntary and non-striated
Skeletal – voluntary and striated , multinucleated
Cardiac – involuntary and striated

Question 25

Describe Nervous tissue?

Answer 25

Consists of neurons and their supporting cells (glia)
Control function and allows for rapid communication between different parts of the body
Surrounded by connective tissue coat

Question 26

What do oligendrocytens and Schwann cells produce?

Answer 26

myelin

Question 27

What are erythocytes?

Answer 27

RED BLOOD CELLS

last around 4 months

Question 28

Describe haemopoiesis?

Answer 28

formation of blood

• earliest site: outside embryo in yolk sac
• then bone marrow

Question 29

Which cells are white blood cells?

Answer 29

Neutrophils
Eosinophils
Lymphocytes
Monocytes

Question 30

What is the tunica intima?

Answer 30

inner layer

single layer of squamous epithelial cells

Question 31

What is the tunica media?

Answer 31

middle layer

smooth muscle interwoven with connective tissue

Question 32

What is the tunica adventitia?

Answer 32

outer layer

supporting connective tissue