Common Integument Structure

Question 1

What is the deepest structure of the common integument?

Answer 1

Subcutis (aka hypodermis)

Question 2

2nd deepest structure of common integument?

Answer 2

Skin (cutis)- dermis and epidermis

Question 3

What is the surface structure of common integument?

Answer 3

Modified skin structures

Question 4

5 examples of modified skin structures

Answer 4

• Hair follicles and hairs
• Skin glands (inc. mammary)
• Foot pads
• Nails claws and hooves
• Horns and antlers

Question 5

Subcutis

Answer 5

Loose connective tissue between skin and muscle fascia
Contains white fat (adipose tissue)
Regional Variations in fat and thickness
Muscle attachments- skin movement: tendons into the subcutis

Question 6

TYPES OF CUTANEOUS MUSCLE: Platysma

Answer 6

Over the neck and face

Question 7

TYPES OF CUTANEOUS MUSCLE: Frontalis

Answer 7

Over the frontal bone (not in horses)

Question 8

TYPES OF CUTANEOUS MUSCLE: Cutaneous colli

Answer 8

From sternum and up neck

Question 9

TYPES OF CUTANEOUS MUSCLE: Cutaneous trunci

Answer 9

covers the side of the trunk

Question 10

TYPES OF CUTANEOUS MUSCLE: cutaneous omobrachialis

Answer 10

continuation of the cutaneous trunci over the shoulder and arm

Question 11

TYPES OF CUTANEOUS MUSCLE: preputial muscles

Answer 11

connect the ventral midline to prepuce.

Question 12

Cutis

Answer 12

Composed of the dermis and the epidermis
Dermis determines skins thickness

Question 13

The Dermis

Answer 13

(in the cutis) made up of fibrous connective tissue- collagen and elastin
Collagen fibres are oriented in tension lines or Langer’s lines

Question 14

The Dermis also contains…

Answer 14

• Blood vessels
• Lymphatic vessels
• Nerves
• Sensory receptors
• Hair follicles
• Arrector pili muscles
• Sebaceous and sweat glands

Question 15

The epidermis

Answer 15

(the surface layer) 4-5 layers of epidermis
keratinocytes (skin cells) are produced in the stratum basale by mitotic cell division
keratinocytes move to surface whilst specialising

Question 16

Name 5 layers of epidermis

Answer 16

• Stratum basale (deepest)
• Stratum spinosum
• Stratum granulosum
• Stratum lucidum
• Stratum corneum (surface)

Question 17

Cells in the epidermis

Answer 17

mostly keratinocytes and corneocytes but also:
- melanocytes: pigment cells to protect against sun radiation
- Langerhans cells: immune cells
- Merkels cells : touch receptors

Question 18

Functions of common integument

Answer 18

PROTECTION: Physical (fat), Radiation (melanocytes) and Epidermal organs (horns and claws)
IMMUNE: physical barrier, immune cells, antimicrobial secretions.
SENSES: receptors, tactile hairs and toruli hairs.
THERMOREGULATION: sweating, hairs, insulation
STORAGE & EXCRETION: fat stores and glands excrete
COMMUNICATION: gland excretions, arrector pili, pigmentation
SELECTIVE PERMEABILITY: respiration, waterproof.

Question 19

embryonic development- gastrulation

Answer 19

3 germ layers are formed: ectoderm (top), mesoderm, and endoderm (bottom)
These eventually make all animals tissues and organs.
The flat layers role into a hollow tube with ectoderm outside and endoderm inside

Question 20

embryonic development- neurulation

Answer 20

Notochard causes the neural groove to form
Gives rise to the epidermis

Question 21

What does each germ layer form?

Answer 21

Ectoderm- epidermal and neural cells
Mesoderm- musculoskeltal system, connective tissues, organs and blood
Endoderm- lining of gut and respiratory system and out pouchings

Question 22

Where are neural crest cells?

Answer 22

in the ectoderm

Question 23

Somites and Dermatomes

Answer 23

at a later embryonic stage mesoderm organises itself into blocks called somites
Dermatome- a segment of dermis from one somite: innervated by one single spinal nerve.

Question 24

Cutaneous Innervation

Answer 24

After exiting vertebrae spinal nerve splits into dorsal and ventral branches
dorsal branches innervate dorsal skin
ventral branches innervate ventral and lateral skin