Anatomy and Physiology

Anatomy and Physiology:

The muscles of the face

There are 43 muscles in the face, most of which are controlled by the seventh cranial nerve (also known as the facial nerve ) This nerve exits the cerebral cortex and emerges from you skull just in front of your ears. It then splits into five primary branches: temporal, zygomatic, buccal, mandibular and cervical.

The facial muscles are just under the skin and they are the muscles that control our expression. When the face moves the muscles contract and they are also responsible for causing wrinkles.

Please see diagram below:

Bones in the face:

The human face has fourteen bones including the lacrimal bones, the zygomatic bones, the vomer, the nasal bones, the inferior nasal conchae, the mandible, the maxillae, and the palatine bones.

Several of these bones exist in pairs, like the zygomatic bones of our cheeks. These 14 bones form the basic shape of the face and are responsible for providing attachments for muscles that make the jaw move and control facial expressions.

Below us a diagram of the bones in the face:

The primary bones of the face are the mandible, maxilla, frontal bone, nasal bones and zygoma.

Human Skin:

It’s the largest organ in the body and it is made up of three layers:

·         Epidermis

·         Dermis

·         Subcutaneous Layer

The skin has many different types of cells and they all play vital roles in the complexity of the skin.

Some functions of the skin include:

·         Protecting the body from infection

·         Protecting the body from the environment around us especially the sun

·         Helping out bodies regulate temperature

·         Protective against excessive loss of water from the body

·         Storage for nutrients

·         Protection of underlying organ and tissues

Epidermis:

The upper or outer layer of the two main layers of cells that make up the skin. The epidermis is mostly made up of flat, scale like cells called squamous cells. Under the squamous cells are round cells called basal cells. The deepest part of the epidermis also contains melanocytes. These cells produce melanin, which gives the skin it’s colour.

The keratinocytes develop from the bottom of the epidermis and rise to the top, where they are shed from the surface as dead skin cells. The epidermis constantly re news itself.

Melanocyte cells produce a dark pigment called melanin, which contributes to skin colour. This also provides UV protection, these are located at the bottom of the epidermis. These cells can then turn into melanoma.

Dermis:

The dermis consists mostly of connective tissue and this much thicker than the epidermis. This layer is responsible for the skin’s strength. It is also involved in the regulation of the body’s temperature.

Blood vessels:

The dermis has a network of tiny capillaries through which the blood circulates. The blood vessels supple the skin with fresh blood, which contains nutrients, oxygen and carries away waste products.

Sebaceous glands:

Sebaceous glands or oil glands are small tiny glands that secrete sebum. This oily substance is a natural moisturizer that naturally conditions the hair and the skin. They are found all over the body, they are significantly more found in the scalp area, around the forehead, chin, cheeks and nose. These glands play a major role in the development of acne.

Sweat glands:

Sweat glands occur all over the body, but are mostly numerous on the forehead, the armpit, the palms and the soles of the feet. Sweat is mainly water, but it also contains some salts. It’s main function is to control body temperature. As the water in the sweat evaporates, the surface of the skin cools. These are sweat producing structures that consist of a coiled body that leads into a duct opening at the skin surface. They are involved in temperature regulation as they help to cool the skin down by sweating.

Sweat glands have simple but important functions

1.    They act as secretory pores and help n removal of waste from the body

2.    They help in maintaining body temperature

3.    They secret oil which keeps pathogens away

Hair follicles:

Hair follicles are canals of epidermis extending downwards into the dermis and they specialise to produce hair.

One of the main functions of hair is to act as a sensitive touch receptor. Sebaceous glands are also associated with each hair follicle that produce an oily secretion to help condition the hair and surrounding skin.

Arrecti pili muscle:

This small muscle is attached to the base of the hair follicle. When it is stimulated by cold or fright it pulls the hair up, causing it to stand upright, closing the skin pores and keeping the warmth in.

Subcutaneous layer:

The subcutaneous layer below the dermis consist of loose network of connective tissue and fat. It acts as a protective barrier and helps the body by monitoring heat gain and heat loss. The thickness of this layer can vary in different individuals.

Fat cells:

Fat is so often seen as the enemy – something to avoid or lose. But fat is also a crucial component of the body. Without it, humans would freeze. Our nerves, uninsulated, would jangle with crisscrossed communications. We’d be unable to store crucial supplies of certain vitamins or have a functioning immune system.

On a cellular level, fats make the membranes that surround cells possible and act as messengers that bind to proteins and enable various reactions.

The main form of a fat cell in the body, this is what most people think of when they talk about fat. Also called “white adipocytes” these fats cells are white, thanks to a low density of mitochondria (microscopic fat burning power plants ) and blood vessels.

Mitochondria are often referred to as the powerhouses of the cell. They help turn the energy we take from food into energy that the cell can use

The cells store fat in the form of triglycerides, padding your energy reserves and body. White fat is the largest energy backup in the body and provides cushion for our organs and external body structure. In addition, it provides cushion for our organs and external body structure. In addition, it produces leptin and a form of oestrogen which regulate hunger, and has receptors for hormones such as growth hormones, cortisol, and insulin.

Triglycerides are a type of fat (lipid) found in your blood.

When you eat, your body converts any calories it doesn’t need to use right away into triglycerides. The triglycerides are stored in your fat cells. Later, hormones release triglycerides for energy between meals.

If you regularly eat more calories than you burn, particularly from high-carbohydrate foods, you may have high triglycerides