Revision Flashcards
what does transcellular fluid include
cerebrospinal fluid
synovial fluid
ocular fluid
pH in plasma vs intracellularly
plasma - 7.4
intracellularly 7.1 = double the [H+]
protein conc intracellularly
10mM
Cl- conc intracellularly
5mM
what happens to the cell if the solution is hypertonic
it shrinks
what happens to the cell if the solution is hypotonic
it swells
how does tonicity define the strength of solution
as how it affects the final volume of the cell
how are substances exchanged through the endothelium
via pores in the cells
what causes oedema
increased permeability of the capillary walls to plasma proteins
what does it mean that APs are non-decremental
size of the AP is maintained throughout transmission
when is Ca returned to the sarcoplasmic reticulum
simultaneous to its release
the rate of active transport back in is lower than the rate of release
what does recruitment mean in terms of muscles
increasing the number of active motor units
what is a motor unit
a single motor neuron and all its fibres
size of cardiac cells compared to SM cells
cardiac are larger
what innervates sm cells
autonomic nerves
are both sm and cardiac cells spontaneously active
yes
what is salbutamol
an agonist
how do tyrosine kinases work
phosphorylating the AA tyrosine
eg GF receptors eg insulin, epidermal and platelet derived
describe G proteins
heterotrimeric
a B and y subunits
have 7 transmembrane couple receptors which when activated stimulate the exchange of GDP to GTP
mechanisms to switch off the intracellular signal
receptor inactivation
receptor down regulation - breakdown by lysosomes
the production of inhibitory proteins
inactivation of intracellular signalling proteins
components of the epidermis
squamous epithelium composed of
keratinocytes, melanocytes, langherhans and merkel cells
what is the dermis
forms the structural foundation of skin containing bv, nerves and adnexal structures - hair follicles, sweat glands and sebaceous glands
what is the hypodermis
a deep subcutaneous adipose layer
acts as fat and heat store
melanin
pigment found in epidermis but not secreted
layers of the epidermis
cells that gradually keritinise to form the waterproofing layer From deep to superficial: stratum basale stratum spinosum stratum granulosum stratum corneum
stratum basale
deepest layer
large nuclei
dense cytoplasm
stratum spinosum
intracellular spines
stratum granulosum
granules containing precureser filaggrin - help bind keratin filaments
stratum corneum
contains dead, flattened cells filled with keratin
hemidesmosomes
on basal surface of epithelial cells
present in dermo-epidermal junctions
attach a single cell to the ECM
desmosomes
attach 2 cells together
adhesion belts
control the assembly of other junctions
tight junctions
form tight seal s between adjacent cells
gap junctions
form continuous pores on adjacent cells allowing for passage of ions between cells
where is hair not found
glaborus skin of palms, soles, glans penis, vulval introitus
lanugo hair
fine and long
formed in foetus at 20weeks - lost at birth
happen with malnutrition - anorexia
vellus hair
short
fine
light coloured
all over the body
terminal hair
longer
thicker
pigmented
found on scalp, eyebrow and eyelashes and pubic, axillary and beard areas
what happens in catagen
cell division slows and stops
shaft keratinises and forms a club shape
dermal papilla and club move to muscle insertion
4-6wks
telogen
hair actively shed and next anaphase begins
time frame of hair growth
anagen 2-6wks
catagen 2-3wks
telogen 2-3 months
nail matrix
contains dividing cells which mature, keratinise and move to form nail plate
can contain melanocytes
nail root
where the nail begins
embedded underneath the skin at the base of the nail
other word for eponychium
cuticle
what is the eponchium
acts as a barrier to the external environment
ensheaths the nail plate from above and below
what is the hyponychium
thickened epidermis that underlies the free margin of the nail
nail bed
produces a small amount of keratin and is adherent to the nail plate
normal morphology of the nail
angle between proximal nail fold and nail plate <180degrees
nail curved in 2 planes and has longitudinal ridges in a proximal to distal direction
