2. Skin (Integument) Flashcards
(26 cards)
How is the skin covered?
The skin is covered with the superficial epidermis, made of epithelial tissue, and the deeper dermis, containing much connective tissue.
Which tissue lies under the dermis?
Under the dermis is the superficial fascia (also called the hypodermis despite NOT being part of the skin).
Describe the build-up of the epidermis
Most superficial layer: waterproof stratum corneum (no living cells)
Stratum corneum
Stratum lucideum
Stratum granulosum
Stratum spinosum
Stratum basale (=stratum germinativum).
What is the goal of the stratum germinatuvum/basale?
In the stratum germinativum keratinocytes are actively dividing. Melanocytes also inhabit this layer and produce melanin.
How are skin macrophages produced?
Dedrocytes migrate to the skin from the bone marrow an become macrophages there
What are the sensory cells of the skin?
Merkel cells are one of the many sensory receptors found in the skin. Merkel cells are associated with a sensory nerve ending.
What is the dermis build up of, except for connective tissue?
- blood capillaries
- hair roots
- sensory receptors (free nerve endings or encapsulated)
- exocrine sweat and oil glands
- connective tissue: collagen and elastic fibres
What is the function of keratin?
Keratin is an extremely important substance for it makes the skin waterproof. Without it, land vertebrates like reptiles, birds, and mammals would, like frogs, be able to survive only in damp places.
The cells in the epidermis die because a special protein called keratin is deposited in them.
What is the difference between exocrine and endocrine glands?
Exocrine glands are glands with ducts.
Endocrine glands have no ducts and release their products (hormones) directly into the bloodstream
What is the difference between cold blooded and warm blooded temperature regulation?
Cold blooded: body temperature follows that of the environment
Warm blooded: body temperature is constant despite changes in the temperature of the environment
Why is it easier for large animals to maintain their body temperature?
In large animals, the ratio of the outside body surface to the inner volume is smaller making it easier to maintain their body temperature
What is regulating body temperature?
The hypothalamus (how?)
Are all vertebrates warm blooded?
No, only birds and mammals can control their body temperature. Ie they are warm blooded or homoiothermic
What is the role of capillaries in the dermis in temperature regulation?
Blood capillaries in the dermis constrict or dilate to control heat loss
How is keratin produced?
Keratin is produced by keratinocytes
Where are sebaceous glands found?
In the dermis. They produce oil
When a medicine is delivered via a patch attached to the skin, how is it delivered?
This is called transdermal delivery
When a pharmaceutical is administered hypodermically, what does this mean?
“Hypo” means below, in this case, the dermis. Subcutaneous fat
(superfi cial fascia) lies beneath the dermis.
Name 5 sensory receptors of the skin
- Meissner corpuscle
- Root hair plexus
- Nociceptor
- Merkel cells
- Pacinian corpuscles
Name 2 types of sweat glands
The apocrine and the eccrine gland
To what in the skin does the term “nociceptors” refer?
Nocireceptors refer to the free nerve endings with large receptive fields that detect pain. The prefix “noci” is derived from the Latin for hurt.
How do sudiferous glands secrete sweat?
Sudiferous glands secrete sweat through a duct to the skin or into a hair follicle.
Eccrine (ander woord: merocrine) sweat glands secrete through a duct, apocrine sweat glands secrete into a hair follicle. (sudiferous gland can be both)
What are the four functions of the skin?
- Produce melanin
- Secrete sebum
- Minimise water loss
- regulate body temperature
What purpose is vitamin D (calcitriol) used for?
Vitamin D is required for uptake of calcium from the gut
