The Skin
The outer epidermis consists of dead cells to stop water loss and protect the body against invasion of pathogens. The hypodermis (below the dermis) contains fatty tissue which insulates the body against heat loss and is a store of energy. The middle layer, the dermis, contains many sensory receptors and is the location of sweat glands, many small blood vessels as well as hair follicles.
Diagram : The structure of human skin
👇🏻Ways to Control Body Temperature 👇🏻
When we are feeling hot.... 🥵🥵🥵
- Sweating
Sweat glands produce sweat, which is secreted on the surface of the skin. It evaporates but needs energy to do so, called the latent heat of vaporization. This is provided by the body’s heat.
- Relaxation of Hair
Hair erector muscles relax to trap a thinner layer of air so more heat can be lost.
- Vasodilation
Blood flows through capillary loops in the dermis, radiating heat to the outside.
When we are feeling cold.... 🥶🥶🥶
- Increase in Metabolism
Stimulated by adrenaline, metabolism can generate more heat.
- Shivering
Muscles contract and relax rapidly to produce heat.
- Vasoconstriction
Blood flows through deeper vessels so less heat is radiated away.
- Piloerection
Also known as goosebumps, this is the result of hairs pulled upright to trap more air which prevents heat conducting away.
Other hormones in our body
In I/GCSE Biology, you are also requireed to know other hormones in our body as below.
- Anti-Diuretic Hormone (Pituitary gland) : Controls water content of blood.
- Adrenaline (Adrenals) : Prepares body to ‘fight’ or ‘flight’.
- Testosterone (Testes) : Controls development of male secondary sexual characteristics.
- Progesterone (Ovaries/Corpus Lueteum) : Regulates menstrual cycle, maintains uterus lining, prevents ovulation…etc.
- Oestrogen (Ovaries) : Controls development of female secondary sexual characteristics.
- Insulin (Pancreas) : Lowers blood glucose.
That's the end of the topic!
Drafted by Joey (Biology)
Reference:
https://www.nursingtimes.net/clinical-archive/dermatology/skin-1-the-structure-and-functions-of-the-skin-25-11-2019/