coordination and control - nervous system - eye - brain- hormones (human+plant) Flashcards
nervous system function
allows communication
CNS - central nervous system
- brain + spinal chord
- revives /processes info - gives out instructions
PNS - peripheral nervous system
- neurones, receptor cells, effectors
- collects info then sends to CNS - acts on instructions from CNS
neurones
- special nervous cells
- motor - sensory - relay
- carry electrical impulses round the body
adaptions of neurones
- long
- myelin sheath - insulates impulses
- numerous dendrites - connections to many neurones
sequence of events
- stimulus - receptor - coordinator - effector - response
sequence of neurones
receptor - sensory - relay - motor - effector
sensory neurones
receptor - sensory - relay (CNS)
dendrites - cell body in middle - receptors
relay neurone
sensory - relay - motor
round with dendrites
motor neurone
relay (CNS) - motor - muscles / glands
cell body - long bit - dendrites
flow of impulse
to dendrites
synapse
GAP BETWEEN NEURONES
- end of cell (electrical- chemical message)
- chemical transmitter molecules carry across synapse
- binds to receptor - open channels
- initiates new nerve impulse
(transmitter taken back to presynaptic neurone)
reflex arc
subconscious response to dangerous stimuli extremely quick (not involve brain)
survival instinct
sight
eye
light
hearing
ear
sound
smell
nose
chemicals in the air
taste
tongues
chemical la in air reacting with tastebuds
touch
skin
pressure pain temperature
reflex arc sequence of events
stimuli- receptor - sensory - relay (spinal cord) - motor - effector - response
voluntary actions
- decide to carry out
- have to think
- slower and purposeful
iris
coloured ring of muscle
- alters pupil size by contracting and reacting
cornea
transparent coating in front of eye
- protects eye refracts light into eye
lens
transparent biconvex lens
- focuses light clearly into the retina
ciliary body
ring of muscle tissues
- alters shape of lens
suspending ligaments
ligament tissues (by ciliary body) - connects ciliary muscle to lens
optic nerve
nervous tissue
- carries nerve impulses to brain
retina
made of light sensitive cells - back of the eye
- cells produce nervous impulse that travels down the optic nerve
pupil
hole in iris
- allows light to enter eye
what makes up the retin
photoreceptor cells
- rods
- cones
rods
respond to light
- allows us to see in low light levels
cones
respond to colours
- different cone cells respond to red, blue and green light
how do we see in dim light
outer RADIAL muscles contract (muscles pull)
- pupil larger
how to see in bright light
inner CIRCULAR muscles contract (muscles bigger)
- pupil smaller
focusing image on the retina
- cornea reflects light
- lens produces further refraction
- an image is in focus on retina
- optic nerve carries nerve impulses to brain
seeing distant objects
- ciliary muscles relax
- suspensory ligaments pull taut
- lens pulled thin
- light doesn’t bend as much
seeing near objects
- ciliary muscles contract
- suspensory ligament slack
- allowing lens to become fat
- bend lights more
accommodation
ability of lens to change shape and allow the eye to focus on objects at diff distances
short sighted - myopia cause
eyeball is too long or cornea is too sharply curved
- light rays meet in front of retina
- image is blurred
long sightedness - hyperopia cause
eyeball too short or cornea not curved enough or lens is too weak (not thick)
- light rays meet past retina
- image is blurred
myopia correction
diverging lens
- light refracted outwards before it hits the lens (diverged) making light rays meet on retina
hyperopia correction
converging lens
- refracts light more (converged) to make the light rays meet on retina
myopia
short sighted
can only see near objects clear
hyperopia
long sighted
can only see far objects
pituitary gland
- stores + releases hormones that regulate bodily functions
little ball
medulla
- controls automatic actions
(heart/breathing rate)
(bottom stem)
cerebellum
- controls involuntary movement posture/balance
big ball at back
cerebrum
- controls complex behaviour (learning memory personality)
big folded bit
how do we know about brain
examine functional changes in people with brain damage
(phineas cage, mike the chicken)
imaging techniques
difficulties of investigating brain function
difficult to obtain + interpret case studies
- ethical issues of investigating brains
hard to treat brain damage
- limited ability to repair nervous tissue
- irreversible damage
- difficult to access parts
endocrine system
- co ordinates organs (work together)
- produces chemical messengers
- produced in small quantities+ transported in blood
- slower
- acts for longer + targets larger area
thyroid gland (hormones)
THYROXINE - regulates metabolic rate (speed to transfer energy from chemical) - controlled by hypothalamus + pituitary gland (negative feedback) \+ excess - hyperactivity - deficiency - overweight + sluggish
ovaries (hormones)
OESTROGEN - development of female sec characteristics - regulates menstrual cycle PROGESTERONE - maintains uterine wall
testes (hormones)
TESTOSTERONE
- promotes development of male sex characteristics
pancreas (hormones)
INSULIN - converts blood glucose > glycogen - increases metabolic rate (stimulates glucose uptake) GLUCAGON -converts glycogen > glucose
pituitary gland (hormones)
STH - bone + muscle growth ADH - reabsorption of water into blood by kidneys TSH - controls function of thyroid FSH - follicle to develop LH - causes ovulation
negative feedback loop
change from optimum receptor detects change processing centre receives/processes info effector brings about change back to optimum
adrenal gland’s (hormones)
ADRENALINE fight/flight - increase heart/ breathing rate - blood diverted to muscles - increases respiration
thyroxine too high
negative feedback
- detected by hypothalamus - inhibits release of TRH
- pituitary stops releasing TSH
- thyroid STOPS producing thyroxine
- return to ideal
thyroxine too low
negative feedback
- detected by hypothalamus - releases TRH
- pituitary releases TSH
- thyroid produces thyroxine
- return to ideal
adrenaline
- causes fight/flight
- increases heart/breathing rate
- blood diverted to muscles
- increases respiration
- breakdown glycogen to glucose
release of adrenaline
- visual stimuli causes fright
- nervous impulses sent to brain + adrenal gland
- release adrenaline
menstrual cycle
28 days
day 1-5 (period) - breakdown uterus lining
day 14 ovulation
age 50-55 - menopause (no menstrual cycle)
menstrual cycle hormones
- pituitary gland > FSH
- FSH - maturation of eggs/ follicle
> OESTROGEN- repairs uterus wall - inhibits FSH + stimulates LH - triggers ovulation
- follicle develops into corpus luteum
> PROGESTERONE - maintains thickness of uterus lining - inhibits FSH + LH
- if egg isn’t fertilised- corpus luteum degenerates - progesteron levels fall
- triggers menstruation
- stops inhibition if FSH (cycle repeats)
FSH
produced - pituitary gland
stimulates follicle + egg maturation
causes oestrogen secretion
oestrogen
produced ovary tissue
builds up/ repairs uterus lining
stops FSH
stimulates LH
LH
produced pituitary gland
causes ovulation
follicle develops into corpus luteum - secretes progesterone
progesterone
produces - corpus luteum maintains uterus lining thickness inhibits FSH+ LH if egg isn’t fertilised corpus luteum degenerates (progesterone levels fall) triggers menstruation FSH inhibition stops
pill
inhibits FSH + LH - inhibits follicle maturation + ovulation
vagina thick with mucus - prevents sperm reaching egg
implant
releases progesterone
inhibits FSH +LH
IUD
releases copper - kills sperm
condom / diaphragm
barrier - blocks sperm
spermicide - kills sperm
causes of infertility
- eggs not mature
- eggs not releasing
- blocks oviducts
- low speed count
- poor quality sperm
infertility treatment
fertility drugs - FSH + LH
surgery (unblock oviducts)
IVF
egg/sperm donation
IVF
egg fertilised in lab with parents egg/speen
- woman given FSH+ LH (stimulate egg maturation)
- egg collected
- eggs mixed with sperm
- monitored and allowed to develop
- one or two selected and placed in uterus
counselling important - must prepare for failure
IVF disadvantages
multiple births may happen
success rate low
strong reaction to hormones
IVF is more successful if woman
is younger has previously been pregnant has BMI in range 19-30 has low alcohol / caffeine intake doesn’t smoke
tropism
growth response of a plant toward or away from stimulus
auxin
found in tips of roots/shoot
no tip = no growth
covered tip grows straight
auxin - shoots
accumulates on shaded side
cell elongation - cell growth
shoot bends towards lightt
auxin - roots
accumulates on lower side
inhibits growth - grow slower
root bends downwards (to gravity)
meristems
found in shoot tip
areas of undifferentiated cells
- divide to form new cells
- can take to grow genetically identical plants (clones)
ethene gas
stimulates conversion of starch > sugar
only gaseous plant hormone
gibberelins
promotes growth - cell elongation
ends dormancy period of seeds/buds
(shoots/flowers open)
auxin uses
- selective weed killer - grow so fast they die (broad leaf)
- rooting powder - promotes new root growth
- prevents ripe fruit dropping- high dose drops all at once
- seedless fruit - applied to unpollinated flowers
gibberelins uses
speed up germination (farmers)
ethene uses
makes fruit ripen fast in time for sale
hypothalamus
- regulates internal conditions (temp, water balance)
- produces major hormones
(above pituitary gland)
negative feedback
respond to change in conditions by initiating responses that will counteract change
maintains steady state
