Integument 1; structure & function Flashcards
(42 cards)
What are the 3 main layers of the common integument?
1) Epidermis
2) Dermis
3) Subcutis (hypodermis)
What other structures are included within the outer integument?
- Hair follicles
- Hairs
- Hooves
- Skin glands
- Mammary glands
- Footpads
- Horns
What is the subcutis?
A loose connective tissue between the skin and the muscle fascia
What are the thicker areas of the subcutis used for and why?
They are used for subcutaneous injections as they can cope with large volumes of fluid being injected.
What does the subcutis mainly contain?
What is this tissue used for?
Contains = adipose tissue (white fat)
Used for = Insulation, Energy source, Padding and protection
What are cutaneous muscles and where are they found?
- Thin, interrupted sheets of muscle
- Found in the subcutis
- Allow for skin movement
Where are each of these cutaneous muscles found?
1) Platysma
2) Frontalis
3) Cutaneous colli
4) Cutaneous trunchi
5) Cutaneous omobrachialis
6) Pre-putial muscles
1) Platysma = over face and neck
2) Frontalis = over frontal bone
3) Cutaneous colli = from sternum, spreads up the neck
4) Cutaneous trunci = covers side of the trunk
5) Cutaneous omobrachialis = Over the shoulder
6) Pre-putial muscles = Along the ventral midline
What is the cutis?
This is the skin, composed of dermis and epidermis.
Which layer of the cutis determines the thickness of the skin?
The dermis
Which muscle is responsible for making hairs on the skin stand up?
Arrector pili muscle
What type of nerve fibres innervate the arrector pilli muscles to make the hairs stand on end?
Sympathetic nerve fibres
What is the dermis?
- A fibrous connective tissue packed with collagen and elastic fibres
- Very few cells.
What type of collagen are found in the dermis?
Types I, III and V
What are the tension lines of an animal’s skin?
Lines determined by the orientation of collagen fibres in the dermis?
What are the two layers of the dermis?
- Superficial papillary region
- Deeper reticular region
What key components are found in the dermis?
- Blood vessels
- Lymph vessels
- Nerves
- Sensory receptors
- Hair follicles
- Arrector pili muscles
- Sebaceous + sweat glands
What is the clinical importance of tension lines?
It is easier to close and incise parallel to these tension lines.
What are the 5 layers of the epidermis?
1) Stratum corneum (TOP)
2) Stratum lucidium
3) Stratum granulosum
4) Stratum spinosum
5) Stratum basale (BOTTOM)
Can Long Giraffe Spines Bend
In which layer are keratinocytes first produced?
In the stratum basale
What happens to these keratinocytes once they have been synthesised?
Move up through the layers, towards the skin surface, differentiating as they do so
What is the function of the stratum basale?
- Provides attachment to the basement membrane
- Proliferation (constant division) of stem cells occurs here
What are the important functions of the stratum spinosum?
- A thick layer in which cells are connected by desmosomes
- Contains dendritic cells important for immune response
What is significant about to the stratum granulosum?
- Keratinocytes contain keratohyalin granules
- Keratohyalin granules contain the products needed for keratinisation (the process of turning keratinocytes-> corneocytes).
Where is the stratum lucidium found?
- A clear layer
- Found only in thick, non-hairy skin
