integumentary system & homeostasis Flashcards
what is the function of the integumentary system?
- body temperature regulation
- protection
- sensation
- excretion
- vitamin D synthesis
- metabolism
- blood reservoir
what is homeostasis?
it is a dynamic state of balance of the body internal environment
how much does your skin weight?
4-5kg
what does epidermis consist of?
keratinised stratified squamous epithelium
what does dermis consist of?
areolar and dense irregular connective tissue
describe keratinocytes
- the most common cell type
- create a physical, tough waterproof barrier
- create and accumulate keratin
describe melanocytes
cells that produce and secrete the pigment melanin
describe dendritic cells
- parts of the immune system
- decrees and consume foreign substances
describe merkels cells
tactile cells involved in your sense of touch
what is stratum corneum?
- most superficial layer
- 20-30 layers of dead cells
- waterproofing glycolipid between cells
what is stratum lucidum?
clear layer found in thick skin only
what is stratum granulosum?
- 1-5 layers of flattened cells
- cells start to degenerate
- cells contain granules
what is stratum spinosum?
- several layers thick gives skin strength and flexibility
- cells joined together by desmosomes
what is stratum basale?
a single layer of stem cells where mitosis occurs and cell differentiation starts here
what is epidermis?
- stratified squamous epithelium
- mainly keratinocytes
- where melanin is produced
- has five layers called strata
what is dermis?
- dense irregular connective tissue
- contains blood vessels, lymphatic vessels and nerves
- glands and hair follicles dip down into this layer
- arealoar connective tissue
- two layers - papillary and reticular layer
what is hypodermis?
- insulation + protection of deeper structures
- under the skin
- adipose tissue
what are sweet glands called?
sudoriferous glands
describe ceruminous glands
- lining of the external ear canal
- produces cerumen (ear wax) which helps to deter insects and block entry to foreign material
describe mammary glands
they make up the glandular tissue in the breast and secrete milk during breastfeeding
oil glands are also known as what?
sebaceous glands
describe eccrine sweat glands
- produces a watery secretion
- involved in thermoregulation
- palms, soles, forehead
- secrete into a pore on the skins surface
describe apocrine sweat glands
- secretion in response to androgens
- secrete into a hair follicle -
- produces a watery secretion that contains some fats and proteins
- stimulated by pain, stress and sex
- screen gland
- axillary + anogenital regions
describe sebaceous glands
- produces an oily secretion
- larger on the face, neck and chest
- softens and lubricates hair
- secreted in response to androgens
- reduces water loss from skin
- secrete into a hair follicle
what are the functions of the skin?
- regulation of body temperature
- protective layer
- sensation
- metabloc functions
- excretion
- blood reservoir
what is the average body temperature ?
37 degrees C
which two organ system allows communication between body organs and coordination of their functions?
endocrine and nervous system
describe the 7 steps in maintaining homeostasis
- stimulus - change inside or outside of the body
- receptor ducts change
- rector send input to control centre
- control centre receive input and determines on response
- output message/instructions sent to effector
- effector changes function
- changes in body function restores homeostasis
how is homeostasis maintained by?
by negative feedback loops. in negative feedback loop the initial stimulus is reserved
when your temperature increases, how does the body cool itself?
vasodilation of the capillaries in the skin causing us to sweat to cool our body down
when your temperature decreases, how does your body warm itself?
vasoconstriction of the capillaries diverted to deeper tissue minimising overall heat loss - shivering to protect heat loss
explain why thermoregulation is describe as being controlled by a negative feedback loop
because when your temperature increases, body changes happen that causes the temperature to decrease and vis versa
what is the initial stimulus that causes oxytocin to be secreted?
stretching of the cervix
what is an example of a positive feedback loop?
labor, blood clotting and milk let down
which endocrine gland secretes the hormone oxytocin?
posterior pituitary gland
