22 Questions
Which sensory receptors are responsible for detecting deep pressure and vibrational changes in the skin?
Pacinian corpuscles
What is the primary function of the subpapillary plexus in the skin?
Nutrition to the skin
Which of the following is an exocrine function of the skin?
Sweat production
What is the primary function of the epidermis in the skin?
Protection from external factors
Which type of burn involves all layers of the skin?
Full-thickness burn
Which of the following is a function of the hypodermis?
Nutrition to the skin
What type of receptors are present in the epidermis to detect pain, light touch, and temperature variations?
Free nerve endings
What is the role of UV light in Vitamin D synthesis?
Conversion of 7-dehydrocalciferol to cholecalciferol
Which of the following is NOT a function of the somatic sensory system in the skin?
Control of pilomotor stimulation at the hair root
What is the main characteristic of the cells in the inner layer of the sebaceous gland?
They are filled with lipid
Which of the following is NOT a type of cutaneous receptor/end organ?
Sebaceous glands
What is the function of the outer cells of the sebaceous gland?
To proliferate and replace degenerated inner cells
What is the term for the discharge of lipid from inner cells of the sebaceous gland?
Holocrine secretion
What is the term for the unit composed of the hair follicle, sebaceous glands, and arrector pili muscle?
Pilosebaceous unit
What is the primary function of merocrine sweat glands in the human body?
Thermoregulation and excretion
Which type of sweat glands are innervated by adrenergic fibres?
Apocrine sweat glands
What is the characteristic of the secretory portion of merocrine sweat glands?
Cuboidal cells resting on a basal lamina
Which glands are limited in distribution to the axillae, areola of the breast, external genitalia, and lower part of the anal canal?
Apocrine sweat glands
What is the characteristic of the ducts of merocrine sweat glands?
Lined with a double layer of cuboidal cells
What is the function of myoepithelial cells in merocrine sweat glands?
Contraction to facilitate sweat secretion
Which glands are associated with hair follicles?
Sebaceous glands
What is the characteristic of the secretion of apocrine sweat glands?
Viscous and protein-rich
Study Notes
Sensory Receptors in the Skin
- Meissner receptors detect light touch
- Merkel's receptors respond to sustained light touch on the skin
- Pacinian corpuscles perceive deep pressure and vibrational changes
- Ruffini endings detect deep pressure and stretching of the skin's collagen fibers
- Free nerve endings in the epidermis respond to pain, light touch, and temperature variations
- Pacinian corpuscles are encapsulated sensory receptors for pressure and vibration located in the deep layers of the dermis and hypodermis
Thermoregulatory Function of the Skin
- Two plexuses are formed by the branching of arteries: cutaneous and subpapillary
- These plexuses provide nutrition to the skin and help in thermoregulation
- Cutaneous plexus is located at the junction of the dermis and hypodermis
- Subpapillary plexus is located at the junction of the reticular and papillary layers
Functions of the Skin (Metabolic)
- Endocrine function: helps in Vitamin D synthesis, which is essential for bone growth
- Vitamin D synthesis involves the conversion of 7-dehydrocalciferol to cholecalciferol by UV light and then to 1,25 dihydroxycholecalciferol in the liver and kidney
- Exocrine function: sweat glands (thermoregulation and excretion of waste) and sebaceous glands (lubrication of skin)
Burns
- Superficial burns: epidermal injury with no blisters
- Full-thickness burns: all layers of the skin are involved
Sebaceous Glands
- Each gland consists of alveoli connected to a broad duct that opens into the hair follicle
- Each alveolus is a pear-shaped, solid mass of cells with hardly any lumen
- Outer cells rest on a basement membrane
- Inner cells are filled with lipid, which is discharged by disintegration of the cells (holocrine secretion)
- Proliferation of outer cells replaces the degenerated inner cells
Hair Follicle and Pilosebaceous Unit
- Hair follicle, sebaceous glands, and arrector pili muscle form the pilosebaceous unit
- Acne vulgaris is a common condition related to the pilosebaceous unit
Innervation of the Skin
- Nerves of the skin include both somatic and autonomic nerves
- Somatic sensory system is responsible for pain, temperature, light touch, discriminative touch, vibration, pressure, and proprioception
- Autonomic innervation is responsible for the control of the tone of the vasculature, pilomotor stimulation at the hair root, and sweating
Sweat Glands
- Merocrine (eccrine) sweat glands: wide spread distribution, produce thin watery secretion, controlled by sympathetic nervous system, important in thermoregulation and excretion
- Apocrine sweat glands: limited distribution, produce viscous secretion, strongly influenced by hormones, begin to function after puberty
- Merocrine sweat glands are innervated by cholinergic fibers
- Apocrine sweat glands are innervated by adrenergic fibers
Mammary Glands and Ceruminous Glands
- Mammary glands: apocrine glands specialized for milk secretion
- Ceruminous glands: found in the ear, secrete ear wax
This quiz covers the different types of sensory receptors found in human skin, including Meissner receptors, Merkel's receptors, Pacinian corpuscles, Ruffini endings, and free nerve endings. Learn about their functions and responses to various stimuli.
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