Integumentary System Flashcards
What are the 2 layers of the cutaneous epithelium?
Epidermis and Dermis
What is the layer that falls below the skin?
Hypodermis
What does the hypodermis consist of?
Areolar connective tissue and fat
What are the 3 sweat glands of the integumentary system?
Sweat, sebaceous and mammary glands
What are some examples of a protective apparatus that is part of the integumentary system?
Hair, feathers, claws, hooves, beak, scales, horns, antlers
What are the main functions of skin?
Protection, sensation, secretion, and subcutis attachment
True or False. Skin acts as a barrier to invaders that are only physical and not chemical.
False. It acts as a barrier for both physical and chemical
In what ways does the skin provide protection?
Protects from physical trauma, acts as a barrier, maintains hydration and protects from radiation
What receptors are associated with the ability of sensation for the skin?
Nociceptors
What stimuli does the skin pick up from the external environment?
Temperature, pressure, and touch
What are some things that the skin secretes?
Sebum, sweat and pheromones
What vitamin does the skin produce?
Vitamin D
How does the skin thermoregulate?
Through sweat glands, hair, and surface area
True or False. One of the skin’s functions is communication.
True
What is the largest organ in the body?
Skin
The external surface of skin is made up of what kind of cells?
Dead keratinized skin cells
Where on the body would you find thick skin?
Nose, pads, abdomen, and scrotum
What are the layers of the epidermis?
Stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum
What type of cells does the stratum basale contain?
Germinal cells, melanocytes and Merkel discs
Is the Epidermis avascular or vascular?
Avascular. It receives its nutrients from the vessel loops within the most superficial layer of the dermis (papillary layer).
What does the stratum spinosum layer of the epidermis contain?
Desmosomes (railroad tracks/ spin) and Langerhans
How can you differentiate the stratum granulosum layer of the epidermis from the others?
It contains glycolipids, which under the microscope look like dark specs within the cells
At what layer do we begin to see the cells of the epidermis lose its organelles?
At the stratum granulosum layer
What role does keratohyaline have in the stratum granulosum layer?
Provide strength
What layer of the epidermis is not found in thin skin?
Stratum lucidum
What is the thickest layer of the epidermis?
Stratum corneum
What are the 2 layers of the Dermis?
Papillary and reticular
What is the most superficial layer of the dermis? Hint: This is attached to the epidermis.
Papillary layer
What types of cells are found in the reticular layer of the dermis?
Fibroblasts and macrophages
What does the reticular layer of the dermis contain?
Hair follicles, collagen fibers, vessels, glands, and smooth muscle
What kind of connective tissue is located in the Hypodermis?
Areolar and elastic connective tissue
What is located in the hypodermis or the sub-q layer of skin?
Connective tissue, fat, vessels, and nerves
What is the name of the nerves located in the hypodermis?
Pacinian corpuscles
What are the two types of nerve endings that help with tactile sense?
Pacinian and Meissner corpuscles
What gives the skin its pigment?
Melanocytes which are located at the stratum basale of the epidermis
Does the nasal planum have thick or thin skin?
Thick skin
How do you determine if an animal’s foot is the front or the back?
Based on the padding, if the foot contains a carpal pad or stopper pad, then it is the front limb
What are the 3 types of pads?
Digital, Metacarpal and carpal
What are the foot pads for?
Protection from physical and thermal stimulus
In what manner do you count the digital pads?
Medial to lateral
What digit is the dewclaw?
Always 1
What are the 2 pad remnants on an equine?
Ergot and the Chestnut
Where is the ergot located?
It is a pad remnant of digits 2 and 4 located near the fetlock
Where is the chestnut located?
Up around the carpus joint or the knee, proximal to the ergot
What are the two types of sweat glands?
Eccrine and apocrine
How do the eccrine sweat glands of the skin secrete?
Through the skin surface
How do apocrine sweat glands of the skin secrete?
Through hair follicles
What is a sebaceous gland?
A small gland in the skin which secretes oily material
In what locations can the amount of secretion of a sebaceous gland vary?
Tail glands, circumanal, anal, circumoral, ceruminous and meibomian glands
What is the muscle that when contracted, makes hair stand on end?
Arrector pili muscle
What part of the hair follicle contains blood and nerve supply?
Dermal papilla
What gland openings does a hair follicle contain?
Sebaceous and apocrine sweat gland openings
What is guard (primary) hair development?
There is an outer coat, the hairs are long and thick and there is one hair/ follicle
What is wool hairs (secondary) development?
There is an undercoat of shorter hair that is soft and each follicle contains multiple strands of hair
What is tactile (vibrissae) hair development?
Follicles located deep into the hypodermis that contains a blood sinus as well as nerve endings that immediately send impulses to the brain
What is an example of a tactile hair?
Whiskers on a cat
What kind of hair growth do dogs and cats have?
Compound hair growth
What is compound hair growth?
Where the animal is developing multiple hairs, both guard and wool
What animals have simple hair growth?
Horses and cows
What is simple hair growth?
Where there is only development of guard (primary) hair
What are the 3 cycles of hair growth?
Anagen, catagen, telogen
What occurs during the anagen hair cycle?
It is when the dermal papillae are very active and hair is actively growing
What occurs during the catagen cycle of hair growth?
When the epidermal peg is starting to change, and the dermal papilla is getting squeezed out, and becomes inactive
What occurs during the telogen phase of hair growth?
It is the resting phase where hair is easy to be pulled out, the hair that’s being shed
What factors is the hair cycle dependent on?
Season, temperature, environment, and hormonal factors
What are the 4 anatomical structures of the claw?
Ungual process, corium, wall (unguis) and sole
What is the ungual process?
The ungual process is the bone portion that sticks into the claw itself, deep to the corium
What is the corium of the claw?
It is considered the dermis of the claw as well as known as the quick
What is the wall (unguis) of the nail?
It’s found on the lateral and dorsal aspects and is the exterior keratinized outer portion of the claw
What is the sole of a claw?
It is the soft portion on the ventral aspect of the claw
What are ungulates?
Hoofed animals
What is the corium of the hoof?
“Sensitive” portion that surrounds the coffin bone
What are the hoof contains a wall that is broken into what 3 parts?
Toe, quarters, and heel
The frog on a hoof is located on what animal only?
Equine
What gives the wall of the hooves such strength?
Interdigitation of the lamina and the corium
What is the lamina of the hoof?
The insensitive portion of cells that interdigitates with the corium
Why is the frog of a hoof important?
It helps with compressing and “pumping” blood out of the limbs back into the heart since the veins don’t contain valves
Where do horns grow from?
At the horn bud on the frontal bone
What is the structure of the horns composed of?
A corium surrounding the frontal bone as well as keratinized epithelial cells and tubules
An animal that should grow horns but does not is considered what?
Polled
What is the name of the growth process for antler bones?
Endochondral Ossification
What is the vascular tissue on the antlers that supply the bone with blood?
Velvets
Does a mouse or an elephant have a greater surface area of skin?
A mouse. It is the ratio between of body weight to the skin’s surface area
What locations do dead, keratinized skin cells change into mucous membrane?
mouth, anus, nares, and eyes
True/False. Is the carpal pad located on the rear legs?
False. Carpal pads are ONLY located on the fore legs.
Do llamas walk on pads or hooves?
Pads
