Human Anatomy and Physiology 1 HT1

Anatomical position

Standard reference position used for described locations and directions on the human body

Anatomy

Science that studies the form and composition of the body’s structures

Anterior

Describes the front or direction toward the front of the body; also referred to as ventral

Cell

Smallest independently functioning unit of all organisms; in animals, a cell contains cytoplasm, composed of fluid and organelles

Cytoplasm

Internal material between the cell membrane and nucleus of a cell, mainly consisting of a water-based fluid called cytosol, within which are all the other organelles and cellular solute and suspended materials

Deep

Describes a position farther from the surface of the body

Distal

Describes a position farther form the point of attachment or the trunk of the body

Homeostasis

Steady state of body systems that living organims maintain

Inferior

Describes a position below or lower than another part of the body proper; near or toward the tail (in humans, the coccyx, or lowest part of the spinal)

Lateral

Describes the side or direction toward the side of the body

Medial

Describes the middle or direction toward the middle of the body

Negative feedback

Homeostatic mechanism that tends to stabilize an upset in the body’s physiological condition by preventing an excessive response to a stimulus, typically as the stimulus is removes.

Nucleus

Cell’s central organelle’ contains the cell’s DNA

Organ

Functionally distinct structure composed of two or more types of tissues.

Organ system

Group of organs that work together to carry out a particular function

Organelle

Any of several different types of membrane-enclosed specialised structures in the cel that perform specific functions for the cell

Physiology

Science that studies the chemistry, biochemistry, and physics of the body’s functions.

Plasma/cell membrane

membrane surround all animal cells, composed of a lipid bilayer interspersed with various molecules; also known as plasma membrane

Positive feedback

Mechanism that intensifies a change in the body’s physiological condition in response to a stimulus .

Posterior

Describes the back or direction toward the back of the body.

Proximal

Describes a position nearer to the point of attachment or the trunk of the body

Superficial

Describes a position nearer to the surface of the body

Superior

Describes a position above or higher than another part of the body proper; also referred to as cranial.

Tissue

Group of similar or closely related cells that act together to perform a specific function

Dermis

Layer of skin between the epidermis and hypodermis, composed mainly of connective tissue and containing blood vessels, hair follicles, sweat glands, and other structures.

Epidermis

Outermost tissue later of the skin

Hair

Keratinous filament growing out of the epidermis

Hypodermis

Connective tissues connecting the integument to the underlying bone and muscle

Keratin

Type of structural protein that gives skin, hair, and nails its hard, water resistant properties.

Keratinocytes

Cell that produces keratin and is the most predominant type of cell found in the epidermis.

Melanin

Pigment that determines the colour of hair and skin

Melanocyte

Cell found in the stratus basale of the epidermis that produces the pigment melanin

Papillary later

Superficial layer of the dermis, made of loose, areolar connective tissue.

Reticular layer

Deeper layer of the dermis; it has a reticulated appearance due to the presence of abundant collagen and elastin fibers

Sebaceous gland

Type of oil gland found in the dermis all over the body and helps to lubricate and waterproof the skin and hair by secreting sedbum.

Sebum

Oily substance that is composed of a mixture of lipids that lubricates the skin and hair

Stratum basale

Deepest layer of the epidermis, made of epidermal stem cells

Stratum corneum

Most superficial layer of the epidermis.

Stratum granulosum

Layer of the epidermis superficial to the stratum spinosm

Stratum lucidum

Layer of the epidermis between the stratum granulosum and stratum corneum, found only in thick skin covering the palms, soles of the feet and digits.

Stratum spinosum

Layer of the epideris superficial to the stratum basale, characterised by the presence of desmosomes