Week 2 Sem 2 Med1022 Flashcards
Bilateral
On both sides of body
Idiopathic
No known cause (for disease/condition etc)
-Mastia
Havin so many breasts or mammary glands (mammary glands= milk producin glands of women/female mammals)
Milk line
Where exessive breast tissue or nipples can grow
Arterial supply of the breast
mainly 2:
internal thoracic (mammary) artery &
Lateral thoracic artery
– Posterior intercostal arteries (2nd-4th intercostal spaces only)
Venous drainage of breast
lateral thoraric vein
Internal thoracic vein
Axilla walls
Has 4 ish walls Anterior wall (pectoralis major etc) Posterior wall (subscapularis etc) Medial wall (chest wall Lateral wall (optional- bicep brachii)
Lymphatic drainage of breast
Most lymph from lateral breast drains into axillary nodes
Medial breast tissue drains into parasternal lymph nodes
Inferior breast tissue can drain to subdiaphragmatic nodes (abdomen)
Contents of axilla
Axillary sheath-containing axially vein/artery n brachial plexus
Outside sheath there r lots of lymph nodes, nerves, axillary fat, biceps brachii etc
ACCESSORY STRUCTURES
structures that funnel or move (TRANSLATE) stimuli to receptor cells. they amplify, modify, channel, focus etc the stimuli.
eg Cornea, Lens, Pupil, etc. act to focus light rays on to the Retina
RECEPTOR CELLS
convert (TRANSDUCE) the physical energy of the stimuli into bioelectrical energy (Receptor or Generator potentials).
eg retina
RECEPTOR SURFACE
receptor cells not randomly dispersed around body; they r
found in discrete areas aka RECEPTOR SURFACE
eg retina is the receptor surface for vision,
e.g. body is the receptor surface for touch.
OUTPUT NEURONES:
carry (TRANSMIT) the information in the form of Action Potentials from receptor cells to CNS
e.g., the optic nerve contains output neurones from the retina
Generator Potential (GP) or Receptor Potential (RP)
when there is a change in resting membrane potential of receptor cells
Mechanoreceptors
stimuli act directly on the cell membrane to affect MECHANICALLY GATED ION CHANNELS, (which then causes GP/RP)
All other types of receptors (apart from mechanoreceptors)
stimuli act on receptors to cause the activation of chemicals within the cell. these chemicals then act on CHEMICALLY GATED ION CHANNELS, (which then causes GP/RP)
Type 1 sensory system
receptors (i.e. the end of the sensory nerves) are specialized nerve endings
produce a GP
GP may cause action potential (AP) in first node of that sensory nerve
Type 2 sensory system
we have specialised receptors that produce RP
RP causes release of transmitter to sensory nerve
which then causes AP in first node of that sensory nerve
Type 3 sensory system
we have specialised receptors that produce RP
RP causes release of transmitter to intermediate cell first, which then release neurotransmitters TO sensory nerve
which then causes AP in first node of that sensory nerve
Intensity coding -one of the “codes” used to signal a particular aspect of stimulus
(the GP/RP allows the receptor to “code” (signal) the presence of stimuli n other info about stimuli.
stronger the stimulus,
bigger the GP/RP
the more AP produced
or
stronger the stimulus
more receptors activated
so more AP produced
Location coding
info is received in particular parts of that brain bit/area/section. i.e. different parts of that brain section is activated when different parts of body does something
Coding of special object properties (colour, pitch)
each receptor is specialised to get one of the smaller bits of stimulus from the larger range of stimulus.
eg different types of photoreceptors best detect different wavelengths of light.
Adaptation
decline in size of RP despite stimulus still being applied to sensory neuron
Coding of change
Each sensory system has receptors/neurons that adapt at different rates- so sensory system can code for wen there is “static” or “dynamic” aspects of a stimulus
