Bio 201 Module 2 Integumentary system Hair Types and Structure part 2

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Questions and Answers

What is the primary function of the nail matrix?

To provide a protective cover for the fingertips

To support the nail during physical activities

To separate the nail from the surrounding skin

To serve as a growth zone for new nail production (correct)

Which part of the nail extends under the overlying skin?

Nail fold

Nail root (correct)

Nail body

Free edge

What is the lunule in the context of nail anatomy?

The opaque white crescent at the proximal end of the nail (correct)

The surrounding skin rising above the nail

The skin underlying the nail plate

The visible part of the nail above the skin

What structure separates the nail fold from the nail plate?

Nail groove Signup and view all the answers

What is the epidermis of the nail bed known as?

Hyponychium Signup and view all the answers

What is the primary source of stem cells for follicle growth?

Hair bulb Signup and view all the answers

Which layer of the hair follicle is derived from the dermis?

Connective tissue root sheath Signup and view all the answers

What determines the texture of hair?

Cross-sectional shape of hair Signup and view all the answers

What causes hair to stand up, creating goosebumps?

Piloerector muscle contraction Signup and view all the answers

Which type of hair contains a high concentration of pheomelanin?

Red hair Signup and view all the answers

What is the primary function of hair receptors?

Sense hair movement Signup and view all the answers

What characterizes gray and white hair?

Presence of air in the medulla Signup and view all the answers

What distinguishes wavy hair from straight and curly hair?

Cross-sectional shape of hair Signup and view all the answers

What type of secretion do apocrine sweat glands actually use?

Merocrine secretion Signup and view all the answers

What type of hair is characterized as fine, downy, and unpigmented that appears in fetuses during the last trimester of development?

Lanugo Signup and view all the answers

How many merocrine sweat glands are typically found in adult skin?

3 to 4 million Signup and view all the answers

Which type of hair is present at birth and is typically found on children?

Vellus Signup and view all the answers

What function do myoepithelial cells serve in merocrine sweat glands?

They contract to help expel perspiration. Signup and view all the answers

What characterizes the secretion produced by merocrine sweat glands?

Watery perspiration Signup and view all the answers

After puberty, which type of hair develops in areas such as the axillary and pubic regions?

Terminal Signup and view all the answers

Which part of the hair is referred to as the swelling at the base where hair originates?

Bulb Signup and view all the answers

Where are merocrine sweat glands primarily located within the skin?

In the dermis and hypodermis Signup and view all the answers

What is the part of the hair that remains within the follicle called?

Root Signup and view all the answers

What is the primary characteristic of terminal hair compared to vellus hair?

It is longer and coarser. Signup and view all the answers

Which component of the hair structure houses blood capillaries that nourish the hair?

Dermal papilla Signup and view all the answers

Which zone of the hair is defined as the portion that extends above the skin surface?

Shaft Signup and view all the answers

Which type of hair comprises two-thirds of the hair of women?

Vellus Signup and view all the answers

What role do sebaceous glands play in relation to hair?

Secrete oils that condition hair Signup and view all the answers

Where are apocrine sweat glands predominantly located in the human body?

Groin and axilla Signup and view all the answers

What characterizes the sweat produced by apocrine glands?

Thick and milky with fatty acids Signup and view all the answers

What physiological role do pheromones play as produced by apocrine sweat glands?

They influence behavior in other members of the species. Signup and view all the answers

What is bromhidrosis?

Disagreeable body odor from bacterial action Signup and view all the answers

Which of the following statements about sebaceous glands is correct?

They release sebum, an oily secretion. Signup and view all the answers

What type of gland are mammary glands considered to be?

Apocrine glands Signup and view all the answers

What is the average composition of sweat produced by sweat glands?

99% water with a pH range of 4 to 6 Signup and view all the answers

How does insensible perspiration differ from diaphoresis?

Insensible perspiration does not produce visible wetness. Signup and view all the answers

Which of the following is NOT a common component of sweat?

Bacterial toxins Signup and view all the answers

What are the mammary ridges or milk lines?

Two rows of mammary glands. Signup and view all the answers

Study Notes

Hair Types

Lanugo: Fine, downy, unpigmented hair that appears on a fetus in the last three months of development
Vellus: Fine, pale hair that replaces lanugo by the time of birth; comprises two-thirds of the hair of women and one-tenth of the hair of men; makes up all the hair of children except for eyebrows, eyelashes, and scalp hair
Terminal: Longer, coarser, and usually more heavily pigmented hair, forming eyebrows, eyelashes, scalp hair, axillary and pubic hair after puberty, and male facial hair.

Hair and Follicle Structure

Bulb: The swelling at the base of the hair where it originates in the dermis or hypodermis; only living hair cells are in or near the bulb
Root: The remainder of the hair within the follicle
Shaft: The portion of the hair above the skin surface

Hair Texture and Color

Texture: Determined by the cross-sectional shape of the hair
- Straight hair is round
- Wavy hair is oval
- Curly hair is relatively flat
Color: Due to pigment granules in the cells of the cortex
- Brown and black hair is rich in eumelanin
- Red hair has a slight amount of eumelanin but a high concentration of pheomelanin
- Blond hair has an intermediate amount of pheomelanin and very little eumelanin
- Gray and white hair have little or no melanin in the cortex and air present in the medulla

Hair Growth and Loss

The hair cycle consists of three developmental stages:
- Anagen: Growth stage
- Catagen: Regression stage
- Telogen: Resting stage

Nail Structure

Nail plate: The hard part of the nail
- Free edge: Overhangs the fingertip
- Nail body: The visible attached part of the nail
- Nail root: Extends proximally under the overlying skin
Nail fold: Surrounding skin rising above the nail
Nail groove: Separates the nail fold from the nail plate
Nail bed: Skin underlying the nail plate; hyponychium is the epidermis of the nail bed
Nail matrix: The growth zone (mitotic) of thickened stratum basale at the proximal end of the nail; responsible for nail growth at a rate of 1 mm per week in fingernails, slightly slower in toenails
- Lunule: The opaque white crescent at the proximal end of the nail due to the thickness of the matrix
Eponychium (cuticle): A narrow zone of dead skin overhanging the proximal end of the nail

Sweat Glands

Merocrine (eccrine) sweat glands: The most numerous skin glands, approximately 3-4 million in adults; simple tubular glands that produce a watery perspiration that helps to cool the body
- Myoepithelial cells: Contract in response to stimulation by the sympathetic nervous system to squeeze perspiration up the duct
Apocrine sweat glands: Found in the groin, anal region, axilla, areola, and bearded areas of mature males; ducts lead to nearby hair follicles; produce a thicker, milky sweat containing fatty acids; scent glands responding to stress and sexual stimulation
- Pheromones: Chemicals that influence the physiology or behavior of other members of the species
- Bromhidrosis: Disagreeable body odor produced by bacterial action on fatty acids

Sebaceous Glands

Produce sebum, an oily secretion that keeps the skin and hair from becoming dry, brittle, and cracked
Flask-shaped glands with short ducts opening into hair follicles
Holocrine glands: Secretion consists of broken-down cells, replaced by mitosis at the base of the gland

Mammary Glands

Breast (mammae) present in both sexes, but mammary glands develop only during pregnancy and lactation.
Mammary glands: Milk-producing glands that are modified apocrine sweat glands.
- Rich secretion released through ducts opening at the nipple.

Skin Disorders

Basal cell carcinoma: Most common, rarely metastasizes
Squamous cell carcinoma: May metastasize
Melanoma: Most dangerous, highly metastatic

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Description

This quiz explores various types of hair, including lanugo, vellus, and terminal hair, as well as their structural components like the bulb, root, and shaft. Learn how hair texture and color are determined and the characteristics of different hair types. Test your knowledge on these essential aspects of human hair biology.