Lecture 17 - accessory structures and fxns

why would threshold for sweating onset be shifted forward if the blood osmolarity is high?

• to prevent further water loss

• the kidneys will also try to hold on to urine as well

what factors would cause sweating to begin at a lower mean body tempurature?

• training

• heat acclimation

• increased skin temperature

What are the three types of interindividual variation in sweat rate?

• bigger gland = higher sweat rate

• “poor” sweater

• moderate sweater

• heavy sweater

what is the physiological significance of sweat?

• thermoregulation via heat dissipation

• skin health

  • epidermal barrier homeostasis → delivery of water, amino acids, NaCl, etc.

• micronutrient balance

  • heat acclimation → conversation of NaCl, bicarb, trace minerals

  • sweat-induced deficiencies (NaCl)

    • prolonged sweating (>8 hrs)

• excretion of environmental contaminants

  • excretion of ethanol → not supported

• excretion of metabolic waste (ex: urea)

  • limited evidence

Sebaceous Glands - types, location, and structure

types:

• attached to hair follicles

• not attached to hair follicles (eyelids, nipples, genitals)

location:

• mid-dermis throughout skin EXCEPT palms/soles

• outlet either into follicular canal or skin surface

structure:

• grape-like clusters of specialized epithelial cells

sebaceous glands functions

• lubrication of skin and hair

• anti-desiccant for epidermis (prevent water loss)

• androgen processing

  • cholesterol → testosterone

• wound healing “keeping them sealed”

• secretion of sebum largely regulated by androgens → teen acne

what is a special function of sebaceous glands

vernix - birth stuff

what is the mechanism of sebaceous glands

• mature cell dies and becomes secretory product 

• holocrine = wHOLe cell breaks down 

ceruminous glands

• specialized apocrine sweat glands; merocrine secretion → exocytosis

• location:

  • subcutaneous layer of the external auditory canal

• function:

  • produces earwax!

    • mix of gland secretion + sebum + dead epidermal cells

  • earwax functions:

    • pliability of eardrum

    • lubrication

    • antimicrobial/acidic

    • particle barrier

mammary glands

• present in all humans to some extent

  • development arrests at the end of puberty in females; differentiation and growth completes during lactation

  • clinical relevance

• location

  • breasts, connected via many ducts to the nipples

• function

  • secrete milk

mammary glands - method of secretion

• apocrine secretion

• pinched off portion of cell is the secretion

• APocrine = APex of cell breaks off