Lab 3 - Epithelial and Connective tissue Flashcards
What is epithelial tissue divided into
- Covering epithelia
- Glandular epithelia
What is connective tissue
- Acellular
- Consists of:
- Ground subsntance
- Different types of fibres
- Small number of various types of cell
What is connective tissue divided into
Loose and Dense
Loose connective tissue
Aereolar
Adipose
Dense connective tissue
Regular
Irregular
What is mesentery
Aerolar loose connective tissue that binds together the loops of intestine.
Guinea Pig Mesentery
Which cells do the smaller, darker, elongate nuclei belong to?
Nucleus of a fibroblast
What is the function of fibroblasts
- Secrete fibres and ground substance
- Thermal insulation,
- Energy store
- Protection against mechanical shock
What fibres are secreted by fibroblasts
Collagen
Where in the eye do you find aereolar connective tissue?
The stroma (body) of the iris
Monkey Gut
What is the white bit…
Lumen
How wide is the lumen of a typical goblet cell
11 micrometers in diameter
Why do all goblet cell lumen not appear to reach the surface of the gut AND what do they secrete
Some lumens look closed – circular shape because of the tissue attached and the angle it has been cut.
Secrete mucus via exocytosis
Which ocular tissue contains goblet cells and why?
Conjunctiva in the upper eyelid. In the conjunctiva goblet cells are a source of mucin in tears and they also secrete different types of mucins onto the ocular surface. Mucus binds aqueous and tear film in your eye + Secrete proteins
Why does the simple columnar epithelium appear to have several layers of nuclei?
Because of the way the cells were cut.
The Skin
What 3 layers does skin contain:
- Outer epidermis
- Underlying dermis
- Hypodermis
What type of epithelium is epidermis and why
Stratified squamous
Protection - Skin easily flakes off if damaged therefore protection is needed so epithelial cells are present at top
What is the outer, acellular, layer of the stratified squamous epithelium composed of?
Dead cells made up of keratin, good for abrasion and waterproof
The outer surface of the cornea has a similar epithelium but the upper, acellular, layer is missing…. Why
So light can get through
What is the shape of the epithelial cells in epidermis
Irregular dense squamous
How thick is the entire epithelium
10micrometres
What is the dermis mostly composed of
Irregular dense connective tissue
What is the main protein component of irregular connective tissue
Collagen and elastin
What is the advantage of irregular arrangement of the fibres
Support and elasticity in all different directions and sizes
What structures does dermis contain
- Hair follicles
- Sebaceous glands
- Sweat glands
- Blood vessels
Why variable appearance of hair follicles
Edges are darker - lots of nuclei. Lumen in centre = white
What are the hairs in hair follicles made of
Keratin
What type of epithelium lines cup in which hair follicles sit
Covering
Sebaceous glands - what is the secretion
Holocrine, whole cell raptures and empties its contents
What is the relationship between sebacceous gland and hair follicle
Sebaceous glands are usually attached to hair follicles and release a fatty substance, sebum, into the follicular duct and thence to the surface of the skin
Function of sebacceous gland
Secretes oil - hydration, lubrication of skin and hair
Why does sweat gland appear to be made up of a series of independent circular structures
Loose adipose tissue containing fat droplets - thermal insulation
What sort of epithelium line blood vessels
Covering
What are the functions of adipose connective tissue?
Thermal insulation + energy store + protect against mechanical shock
What adipose connective tissue is associated with the eye?
Loose adipose connective tissue around outside of eye – surrounds lacrimal gland.
How many layers of cells is the epithelium made of?
5
What type of epithelium is sweat gland composed of?
Simple cuboidal epithelium
Describe the range of diameters of the blood vessels you observe
25um
Can you distinguish arteries from veins?
Veins are generally larger in diameter, carry more blood volume and have thinner walls in proportion to their lumen. Arteries are smaller, have thicker walls in proportion to their lumen and carry blood under higher pressure than veins.
What sort of epithelium is blood vessels lined with
Simple squamous endothelium
What is the average size of the adipocytes?
38um in diameter
Why are these cells sometimes referred to as ‘signet ring’ cells?
Due to accumulation of fat particles in the cytoplasm, the nucleus of the adipose cell moves towards the cell membrane giving a look alike ring
