BIOS 251 Anatomy and Physiology
Exam 2 updated 2025 (Answered) 100%
Verified.
Functions of the Integumentary System
-Resistance to trauma and infection
-Prevents loss or gain of water
-Vitamin D synthesis
-Sensory receptors for heat, cold, touch, texture, pressure, vibration, and tissue injury
-Thermoregulation
How does skin resist trauma and infection?
-Skin has low pH to reduce bacteria and fungi
-Cells are packed closely together with tough protein called keratin
Name 3 ways the integumentary system thermoregulates?
-Glands release sweat for evaporative cooling
- Vasoconstriction
- Vasodilation
Define: Vasoconstriction
narrowing of blood vessels, reduces heat loss
Define: Vasodilation
widening of blood vessels, increases heat loss
What are the 2 main parts of the integumentary system?
Epidermis- outer layer
Dermis- underlying connective tissue
Hypodermis not really part of the skin!
What does the epidermis primarily consist of?
keratinized stratified squamous epithelium
What are the epidermal derivatives?
glands, hair, nails
What are the 4 main cell types in the epidermis?
- Karatinocytes
,- Melanocytes
- Tactile (Merkel) cells
- Dendritic (Langerhans) cells
Keratinocytes (functions)
most numerous cell type, make fibrous protein keratin
Melanocytes (functions)
synthesize pigment called melanin
Tactile cells (functions and 2nd name)
also called Merkel cells, receptors for the sense of touch, associated with a dermal nerve fiber
Dendritic cells (functions and 2nd name)
macrophages (big phagocytic cells) that kill microbes
What are the layers of the epidermis (list from bottom up)?
- Stratum basale
- Stratum spinosum
- Stratum granulosum
- Stratum lucidum
- Stratum corneum
What layer of the epidermis is only found in thick skin?
Straum lucidum
How many layers are found in the stratum basale?
1 layer
What cells are found in the stratum basale?
stem cells, keratinocytes, melanocytes, tactile (merkel) cells
What is the importance of the stem cells in the stratum basale?
makes it mitotically active, the stem cells divide and give rise to keratinocytes
How many layers are in the stratum spinosum?
8-10 layers
What is the appearance of the cells in the stratum spinosum, and why?
The cells are flattened, which happens as they are pushed upward
, What is contained in the stratum spinosum?
Keratinocytes, dendridic (langerhans) cells
In which epidermis layers do keratinocytes produce waterproofing substances?
Stratum spinosum, stratum granulosum
What are the waterproofing substances produced by the keratinocytes?
keratin, lipids
How many layers are in the stratum granulosum?
3-5 layers
In what layer do the nuclei and organelles begin to degenerate in the keratinocytes?
stratum granulosum
What do the cells look like in the stratum granulosum and why?
They continue to flatten because of accumulation of keratin
How many layers are in the stratum lucidum, and what do they look like?
3-4 layers of translucent cells
Why are the cells in the stratum lucidum translucent?
the clear protein named eleidin
How many layers are in the stratum corneum?
up to 30 layers
What do the layers of the stratum corneum consist of?
dead scaly keratinized cells
What are 2 of the main purposes of the stratum corneum?
resistance to abrasion and water loss
What are the layers of the dermis (from top to bottom)?
Papillary layer
Reticular layer
Exam 2 updated 2025 (Answered) 100%
Verified.
Functions of the Integumentary System
-Resistance to trauma and infection
-Prevents loss or gain of water
-Vitamin D synthesis
-Sensory receptors for heat, cold, touch, texture, pressure, vibration, and tissue injury
-Thermoregulation
How does skin resist trauma and infection?
-Skin has low pH to reduce bacteria and fungi
-Cells are packed closely together with tough protein called keratin
Name 3 ways the integumentary system thermoregulates?
-Glands release sweat for evaporative cooling
- Vasoconstriction
- Vasodilation
Define: Vasoconstriction
narrowing of blood vessels, reduces heat loss
Define: Vasodilation
widening of blood vessels, increases heat loss
What are the 2 main parts of the integumentary system?
Epidermis- outer layer
Dermis- underlying connective tissue
Hypodermis not really part of the skin!
What does the epidermis primarily consist of?
keratinized stratified squamous epithelium
What are the epidermal derivatives?
glands, hair, nails
What are the 4 main cell types in the epidermis?
- Karatinocytes
,- Melanocytes
- Tactile (Merkel) cells
- Dendritic (Langerhans) cells
Keratinocytes (functions)
most numerous cell type, make fibrous protein keratin
Melanocytes (functions)
synthesize pigment called melanin
Tactile cells (functions and 2nd name)
also called Merkel cells, receptors for the sense of touch, associated with a dermal nerve fiber
Dendritic cells (functions and 2nd name)
macrophages (big phagocytic cells) that kill microbes
What are the layers of the epidermis (list from bottom up)?
- Stratum basale
- Stratum spinosum
- Stratum granulosum
- Stratum lucidum
- Stratum corneum
What layer of the epidermis is only found in thick skin?
Straum lucidum
How many layers are found in the stratum basale?
1 layer
What cells are found in the stratum basale?
stem cells, keratinocytes, melanocytes, tactile (merkel) cells
What is the importance of the stem cells in the stratum basale?
makes it mitotically active, the stem cells divide and give rise to keratinocytes
How many layers are in the stratum spinosum?
8-10 layers
What is the appearance of the cells in the stratum spinosum, and why?
The cells are flattened, which happens as they are pushed upward
, What is contained in the stratum spinosum?
Keratinocytes, dendridic (langerhans) cells
In which epidermis layers do keratinocytes produce waterproofing substances?
Stratum spinosum, stratum granulosum
What are the waterproofing substances produced by the keratinocytes?
keratin, lipids
How many layers are in the stratum granulosum?
3-5 layers
In what layer do the nuclei and organelles begin to degenerate in the keratinocytes?
stratum granulosum
What do the cells look like in the stratum granulosum and why?
They continue to flatten because of accumulation of keratin
How many layers are in the stratum lucidum, and what do they look like?
3-4 layers of translucent cells
Why are the cells in the stratum lucidum translucent?
the clear protein named eleidin
How many layers are in the stratum corneum?
up to 30 layers
What do the layers of the stratum corneum consist of?
dead scaly keratinized cells
What are 2 of the main purposes of the stratum corneum?
resistance to abrasion and water loss
What are the layers of the dermis (from top to bottom)?
Papillary layer
Reticular layer
