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Cumulative Review 3 for Final Exam BIOL 319

Terms in this set (38)

Compare the degree of vascularization and innervation between the epidermis and dermis? Also, how do these compare in term of relative thickness?
Epidermis: avascular & not innervated
Dermis: vascular & innervated; a lot thicker than epidermis
What two types of tissue make up the dermis? What is their relative location and thicknesses?
Papillary layer: uppermost 20%; made up of areolar connective tissue
Reticular layer: deeper 80%; made up of dense irregular connective tissue
Oil glands (aka sebaceous glands) structure & function
produce holocrine secretions (cells apoptose and become the secretion itself); lubricate hair & skin to keep them from falling apart; has defensin (protein that kills bacteria)
Hair structure & function
functions are sensory, protection, sexual signaling (distinguish btw male & female)
Terminal hair: medulla→ cortex→ cuticle (outermost)
Vellus hair: cortex→ cuticle (outermost)
Hair follicle structure & function
anchors hair and provides a place for it to grow; its nerve plexus are sensitive to follicle movement
Epidermal layer: innermost layer of follicle; invagination of epidermis
Dermal layer: outermost layer of follicle
Mini organ: has 2 types of tissues and does a discrete job
Arrector pili muscle structure & function
involuntary; creates goosebumps and hair to stand up when contracted (usually due to cold temp, anger/other heightened emotions)
Eccrine sweat glands structure & function
important for thermoregulation; located throughout the body (concentrated in areas where you sweat: trunk, neck, head); sweat is mostly water but also has ions; creates an acid mantle when it evaporates (retards bacteria)
Apocrine sweat glands structure & function
responsible for malodorous sweat (secretion is odorless but bacteria on the skin eat the lipid & protein in the sweat and their waste products produce the bad smell); located in the axillary & groin region; activated at puberty
Do oil and sweat have other functions aside from evaporative cooling and lubrication, respectively? Explain.
They both serve to keep bacteria at bay. Oil has defensin, a protein that perforates holes in bacteria and kills them. Sweat is acidic, so its acid mantle serves as a chemical protection from bacteria.
In humans, how does the: (1) distribution and (2) thickness of terminal hair compare with other familiar mammals?
Humans don't have as much terminal hair and it is not as thick as other mammals. For this reason, we cannot use our hair for thermoregulation or emotional signaling (but mammals can).
What is vellus hair?
thinner & shorter unpigmented hair (peach fuzz) located throughout the body in abundance; helps us feel things that are close to the body but not directly touching it; NO medulla
What is terminal hair?
thick, long & pigmented; located in the nose, eyelashes, eyebrows, on head, forearms, forelegs, and pubic & axillary region (appear during puberty); has a medulla
What are the layers and relative position of layers that make up terminal hair?
Terminal hair: medulla→ cortex→ cuticle (outermost)
What is (are) a major function(s) of hair in humans (hint: one has a tight relationship with the nervous system).
Sensory: nerve plexus in hair follicle makes it sensitive to movement (if a hair is bent can feel things that are close to the body but not directly touching it)
Protection: hair on head protects from UV rays or things that fall on head; eyebrows, eyelashes, & nose hair prevent things from coming inside the body
Sexual signaling: indicate male vs female
Does hair in humans have any protective role? Explain.
Yes, hair on the head protects from UV rays and things that fall on the head. Also, eyebrows, eyelashes, and nose hair prevent things from coming inside the body.
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