Quick Review Flashcards - Click to flip and test your knowledge!
Question
The human skin accounts for approximately what percentage of an adult's total body weight?
Answer
$15\%$
Question
Which organ is considered the largest in the human body?
Answer
The skin
Question
To which organ system does the skin belong?
Answer
Integumentary system
Question
How does the skin protect the body from mechanical shocks?
Answer
By protecting the underlying tissues.
Question
The skin prevents the excessive loss of _____ by evaporation.
Answer
Water
Question
What type of light does the skin block to protect the body from potential harm?
Answer
Ultraviolet light
Question
As a sense organ, what are two specific stimuli the skin can detect?
Answer
Touch and pressure (or pain and heat).
Question
In what form does the skin store reserve food?
Answer
A layer of fat contained in special cells.
Question
Besides water and salts, what metabolic waste is excreted in limited amounts through sweat?
Answer
Urea
Question
The skin synthesises _____ when exposed to sunshine.
Answer
Vitamin D
Question
What physical change occurs in the skin of fingertips after prolonged exposure to water to improve grip?
Answer
The skin wrinkles or puckers up.
Question
The skin proper is composed of which two primary layers?
Answer
The outer epidermis and the inner dermis.
Question
The epidermis is formed of _____ epithelium piled up layer after layer.
Answer
Stratified
Question
True or False: The epidermis contains numerous blood vessels to nourish its cells.
Answer
False
Question
Name the outermost sublayer of the epidermis.
Answer
Cornified layer (stratum corneum)
Question
Which fibrous structural protein is found in the cornified layer of the skin, as well as in hair and nails?
Answer
Keratin
Question
From which deeper layer are the shed cells of the cornified layer replaced?
Answer
The Malpighian layer
Question
The thin middle layer of the epidermis, consisting of flattened cells, is known as the _____ layer.
Answer
Granular
Question
What is the alternative name for the Malpighian layer of the epidermis?
Answer
Germinative layer (stratum malpighi)
Question
In which specific sublayer of the epidermis does active cell division occur?
Answer
The Malpighian layer
Question
Which pigment is responsible for the colouration of human skin?
Answer
Melanin
Question
In which sublayer of the epidermis is the pigment melanin contained?
Answer
The Malpighian layer
Question
Term: Leukoderma (Vitiligo)
Answer
Definition: A condition where skin pigmentation is lost in smaller or larger patches at different regions of the body.
Question
What condition is characterised by the complete loss of pigmentation in the skin, hair, and irises?
Answer
Albinism
Question
Why does the skin of an individual with albinism appear pinkish?
Answer
Because of the underlying blood capillaries showing through.
Question
The dermis is primarily composed of connective tissue containing _____ fibres.
Answer
Elastic
Question
Where on the human body is the dermis found to be the thickest?
Answer
The palms and soles
Question
Where on the human body is the dermis found to be the thinnest?
Answer
The eyelids
Question
What are the small processes in the outer region of the dermis that contain blood capillaries and nerve endings?
Answer
Papillae
Question
What is the primary function of the adipose tissue located beneath the dermis?
Answer
It serves as a food reserve, a heat insulator, and a shock absorber.
Question
List the five special derivatives of the human skin.
Answer
Hair, nails, sebaceous glands, sweat glands, and mammary glands.
Question
Which part of the hair projects from the skin's surface?
Answer
Hair shaft
Question
The lowest part of the hair root is expanded to form the _____.
Answer
Hair bulb
Question
The _____ is a structure enclosing the hair root, composed of an epithelial and a connective tissue sheath.
Answer
Hair follicle
Question
What causes hair to become grey or silvery in appearance?
Answer
A decrease in melanin production.
Question
What is the technical term for 'gooseflesh', where hair is lifted by the contraction of muscles?
Answer
Piloerection
Question
Which muscle is responsible for pulling the hair into a vertical position during piloerection?
Answer
Erector (or arrector) muscle
Question
How do hairs provide a sensation of touch?
Answer
Nerve fibres extend up to the bases of hair follicles.
Question
What is the specific function of eyelashes?
Answer
To help prevent the entry of foreign particles into the eyes.
Question
The hard and outer part of a nail, made of dead keratinised cells, is called the _____.
Answer
Plate
Question
Which part of the nail produces new cells that push older cells toward the tip?
Answer
The matrix
Question
What is the name of the whitish half-moon visible at the base of the nail?
Answer
The lunula
Question
Sebaceous glands usually open into a _____, though sometimes they open directly to the outside.
Answer
Hair follicle
Question
What is the name of the oily secretion produced by sebaceous glands?
Answer
Sebum
Question
How does sebum protect the skin in cold and dry weather?
Answer
It keeps the epidermis supple and prevents loss of moisture by evaporation.
Question
What occurs when an open skin pore is clogged with dead skin cells and sebum, then oxidises?
Answer
A blackhead forms.
Question
A sweat gland consists of a deeper _____ part and an excretory part.
Answer
Secretory
Question
Approximately how many sweat pores are estimated to be in the human body?
Answer
About two million
Question
Where on the body are sweat pores most numerous?
Answer
The palms of the hands
Question
What percentage of sweat is typically composed of water?
Answer
$99\%$
Question
The urea lost through sweat accounts for approximately what percentage of total urea excreted by the body?
Answer
$1\%$
Question
Mammary glands are considered to be modified _____ glands.
Answer
Sweat
Question
Which hormone is responsible for the activity of the mammary glands related to pregnancy?
Answer
Prolactin
Question
What are the modified sebaceous glands found on the margins of the eyelids?
Answer
Meibomian glands
Question
What is the function of the secretion from ceruminous glands?
Answer
It lubricates and protects the delicate eardrum from dust and germs.
Question
Organisms that maintain a more or less constant body temperature regardless of the external environment are called _____.
Answer
Warm-blooded (Endothermal or Homeothermal)
Question
What is the common term for poikilothermal organisms, such as frogs, whose body temperature fluctuates with the environment?
Answer
Cold-blooded (Ectothermal)
Question
What is the average human body temperature when measured in the mouth?
Answer
About $37^{\circ}C$ (or $98.6^{\circ}F$)
Question
At what time of day is human body temperature typically at its lowest?
Answer
Early morning
Question
Name the primary organ responsible for heat production in the body through chemical reactions.
Answer
The liver