Exam 2 Review (chapters 5 And 6) Flashcards
What is the resting membrane potential and how is it set?
-70mV. It is set by K+ leaving the cell through potassium leakage channels, and K+ being a positive ion leaving the cell causes the inside of the cell to become more negative
What would happen if Na+ leakage channels were more numerous or more effective than K+ leakage channels
Resting membrane potential would be less negative, possibly even positive
First distinct layer of the skin
Epidermis
Second distinct layer of the skin
Dermis
Describe the epidermis
Epithelial tissue, no blood vessels, small layer
Describe the dermis
Connective tissue, has blood vessels, large layer
Layer that surrounds muscles
Hypodermis/superficial fascia
What are the functions of the hypodermis/superficial fascia
Stores fat, anchor for skin, shock absorber, insulation
Most abundant epidermis cells with lots of desmosomes and tight junctions
Keratinocytes
Spider shape cells that make a pigment important for UV protection
Melanocytes
Cells that provide an immune function
Dendritic cells
Cells that sense pain, temperature, and touch
Tactile cells
Where are keratinocytes found
In the epidermis
Where are melanocytes found
In the epidermis
Where are dendritic cells found
In the epidermis
Where are tactile cells found
In the epidermis
What are the 5 layers of the epidermis, superficial to deep
- Stratum corneum
- Stratum lucidum (only thick skin)
- Stratum granulosum
- Stratum spinosum
- Stratum basale
What is the function of the stratum basale
Germination
Describe the stratum basale
Single layer of stem cells that create new cells
What kind of cells does the stratum basale give rise to
Most specialize into keratinocytes, 10-25% are melanocytes
Describe the stratum spinosum
Spikes are pre-keratin tonofilaments, lots of dendritic cells, several layers thick
Function of stratum spinosum
Spikes are anchored to desmosomes to resist tension
Describe the stratum granulosum
1-5 layers thick, has keratohyaline (keratin precursor) and lamellar (produce glycoside, water resistant)
What is keratohyaline
The keratin precursor
What are lamella
Granules that produce glycolipids for water resistance
What is the function of the stratum granulosum
Starts the process of keratinization, prevents water loss from lipids and tight junctions,
Describe the stratum lucidum
Only thick skin has the stratum lucidum, looks translucent
Describe the stratum corneum
Most superficial layer, 20-30 layers thick, made up of dead, anucleated, keratin-filled cells
Most superficial layer of dermis
Papillary layer (“nipple”)
Layer underneath papillary layer
Reticular layer
Describe the papillary layer
Sensory receptors, blood vessels, loose aereolar connective tissue
Describe the reticular layer
Dense irregular connective tissue, makes up 80% of thickness
What pigment does melanin provide
Reddish yellow to brown
What pigment does carotene provide
Yellow to orange
Where does the carotene pigment accumulate
In the corneum
What are tonofilaments
Keratin-containing intermediate filaments
One of the functions of skin is to produce the vitamin D precursor, which layer is responsible and why
Stratum granulosum, you want active cells
Which skin layer releases glycolipid effectively walling them off from nutrients in deeper tissue layers
Stratum granulosum
Which is the thickest layer of skin
Stratum corneum
Which layer of skin produces all the other layers
Stratum basale
Function of Myoepithelial cells around secretory glands
Contract in order to aide in secretion
Two sweat glands that secrete through exocytosis
Eccrine and apocrine glands
Official term for glands that secrete by exocytosis
Merocrine glands
Composition of sweat from eccrine glands
- 99% water
- Salt
- Traces of metabolic waste
pH of sweat
4-6
Function of eccrine glands
Temperature regulation
How abundant are apocrine glands
A couple thousand
Here are apocrine glands found
Axillary, rectal, and genital regions
What do apocrine glands empty into
Hair follicles
Composition of sweat from apocrine glands
- 99% water
- Salt
- Traces of metabolic waste
- Lipid and protein substances (specific to apocrine glands)
When are apocrine glands active
At puberty
Function of apocrine glands
Sex scent gland
What are the two modified apocrine glands
Ceruminous glands and mammary glands
What do ceruminous glands secrete
Ear wax or cerumin
What do mammary glands secrete
Milk
Type of gland that explodes to release its product
Sebaceous/oil glands
Official name for glands that explode to release their product
Halocrine glands
Where are sebaceous/oil glands found
Everywhere except thick skin
What do sebaceous/oil glands secrete
Oily substance called sebum
What forces sebum to the surface
Arrector pili muscles
What happens when the arrector pili muscles force sebum to the surface (function of sebum)
Softens and lubricates hair and skin, and is also bacteriacidal
When are sebaceous/oil glands more active
During puberty
Six functions of the skin
Protection, temperature regulation, blood reservoir, cutaneous sensation, metabolic function, excretion
Three categories of skin protection
Chemical, physical, and biological
Chemical protection methods of the skin
- Acid mantle = prevents bacterial growth
- Defensins = poke holes in bacteria
- Melanin = UV protection for DNA
Physical protection methods of the skin
Corneum = brick and mortar layer, cells are the bricks and glycolipids are the mortar
Biological protection methods of the skin
Dendritic cells and macrophages = run the immune responses, both capable of phagocytosis
Two types of temperature regulation
Insensible perspiration and sensible perspiration
What is insensible perspiration
General perspiration at normal temperatures