Plant and Animal Responses Flashcards
2 types of cells that make up the NS?
Neurons & glial cells
Neurons?
transmit via APs
Glial cells?
help nutrients pass into neurons, help balance the conc of ions, myelination (Schwann cells), phagocytosis, may be involved in stimulating the formation of new synapses
2 branches of the NS?
Central nervous system & peripheral nervous system
2 branches of the peripheral NS?
somatic NS and autonomic NS
Autonomic NS?
• Anything that happens w/o thought = automatic
• input: internal muscles
output: SM & glands
2 branches of autonomic NS?
- Sympathetic NS
* Parasympathetic NS
Peripheral NS?
all neurons outside CNS
Somatic NS?
- All to skeletal NS
* conscious control
CNS?
= brain and SC
• majority of this is intermediate neurons
• includes meninges
meninges?
- made of 3 layers
- protect CNS from pathogens and mechanical damage
- secretes CSF (specialised TF)
- The meninges are the connective tissue coverings of the brain and SC
Cerebro spinal fluid?
- specialised TF
* Fills spaces in brain and & SC and therefore acts as a shock absorbed, also provides nutrients and O2 to cells
Gyri of the brain?
the ridges
sulci=
the grooves
-itis?
inflammation
CNS?
- Mainly IN, short dendrites, as many as 200,000 synapses with neighbouring cells (role to integrate)
- synapses can be excitatory or inhibitory (prevents AP)
- SC is really just an extension of the brain, connects and runs down the spinal canal as far as the lumber region
in the centre of the SC…
is CSF
PNS?
- All of the neurons outside CNS
- contains all of the neurons that connect CNS to the rest of the body
- SN carry nerve impulses from receptors to CNS
- motor neurons which carry APs from CNS to effectors
- function of the PNS is to connect CNS to periphery of the body
SN?
• Carry afferent APs from PNS ➡ CNS - sensory input
motor output?
• MN carry efferent APs from CNS to effectors
Autonomic NS?
- The Para NS and Sympa NS are antagonistic
- when one is inhibited, other is activated
- contains all motor neurons to internal organs
- controls all SM and cardiac muscl
- self adjusting
cell bodies of MN are outside the?
CNS, unlike somatic which go all the way to the effector
if a neuron goes outside,
look at cell body to determine if CNS or PNS
Autonomic cell bodies?
- situated in autonomic ganglia
* all contain a preganglionic neuron which carries AP from CNS to ganglion
Sympathetic NS?
- Axons of preganglionic neuron leave ventral root
- synapse at the ganglia
- goes to all organs
- noradrenaline used
- some use ACh (sweat glands, some blood vessels)
- fight or flight
- all signals via spinal nerves which go to ganglions
fight or flight repsonse?
response to stress, causes release of adrenaline
parasympathetic and sympathetic are?
- antagonistic
* when one is stimulated, other is inhibited
fight or flight?
- release of adrenaline
- ⬆resp, ⬆HR, ⬆BR
- contraction of radial muscles of the iris to dilate pupil
- relax urethera sphincter and relax anal sphincter
- constriction of arterioles in DS
- dilation of arterioles in skeletal muscles
- saliva production stopped to save water and energy
Parasympathetic NS?
- All nerve pathways are either at the top or base of the SC
- No Ganglion - synapse just before the effector organ
- most neurons leave at the top in a large nerve called the vagus nerve
- NT is Ach, usually inhibitory, but cab be excitatory
Rest and digest?
- stimulates digestive activity - peristalsis - SM contracting pushing things along
- salivary glands
- not a very sig effect
which muscles contract causing the pupil to constrict?
circular muscles
The reflex arc?
stimulus ➡ receptor ➡ SC not CNS ➡ Effector ➡ response
a reflex is?
involuntary, stereotyped response to a sensory stimulus - often a survival or protective response
the knee-jerk reflex?
- used by the body to maintain posture and balance, allowing us to remain balanced with little conscious thought
- pain receptors in the knee detect hammer
- send signals down a sensory neuron to CNS which enter CNS thru dorsal route
- MN activated wihin SC
- MN carries AP to effector down ventral route
- effector (flexor muscle) contracts
reflexes can be used ti?
diagnose issues with SC. Specific reflexes test spec spinal nerves
Brain?
• controls how we perceive, think, learn, remember e.g.
Gross structure of the brain?
- Hindbrain
- Midbrain
- Forebrain
Hindbrain?
Pons, medulla oblongata, cerebellum
Midbrain?
Brain stem in Midbrain and hindbrain
Forebrain?
- Cerebrum
- thalamus
- hypothalamus
cerebrum?
learning, memory, personality, conscious thought
cerebellum?
unconscious functions, posture and balance
hypothalamus?
regulator centre, temp, H2O - contains osmoreceptors
medulla oblongata?
controls autonomic NS, HR, breathing
pituitary gland?
hormones
5 main brain areas?
- cerebellum
- hypothalamus
- MO
- cerebrum
- pituitary gland
Cerebrum [detailed]
- largest part, covers rest of the brain, it’s the visible surface of the brain
- reecives sensory info ➡relates this info to past exp➡ sends impulse down MN to effectors
- controls all voluntary responses & some involuntary
cerebrum has 2 hemispheres?
L&R - connected via corpus callosum
frontal lobe?
- part of cerebrum
* most reasoning/ decision making
outer layer of cerebrum is known as?
cerebral cortex
why does the right side of the brain receive signals from the left side of the body?
• neurons cross over at the back of the brain
Cerebral cortex main areas?
- frontal lobe
- parietal lobe
- temporal lobes
- occipital lobe
frontal lobe?
intelligence, personality, thought
parietal lobe?
sensory and motor function
temporal lobe?
emotion/auditory
occipital lobe?
visual
3 main types of functional area in the CC?
- sensory areas
- association areas
- motor areas
sensory areas?
receive APs from sense organs - input
association areas?
process and co-ordinate sensory input - form associations with prev. exps - processing
motor areas?
APs generated and sent to effectors - output
Sensory area, association areas, motor areas
- each sensory area receives info from receptor cells
- size of sensory area is dependent on the sense organ
- impulse then goes to association area (analysed)
- impulse sent to motor areas, which send impulse down a NM to effector
main area of motor function?
primary cortex just at the back of the frontal lobe
association areas are often found close to?
corresponding senory areas
cerebellum?
- does not initiate movement, just co-ordinates
- balance receptors in the ear signal
- tweaks by changing tones in muscles and tendons
- receives input from sensory areas
- outputs APs to motor areas to fine tune motor activity
pons?
- relays AP from forebrain to cerebellum
* sleep, posture
hippocampus?
- short term ➡ long term memory
* part of limbic system - emotions
hypothalamus?
- area of forebrain found just above PG
- links NS and ES thru PG
- produces releasing factors which cause the anterior pituitary to release hormones e.g. growth hormone
- contains receptors like osmoreceptors which cause neurosecretory cells to release hormones into capillaries of posterior pituitary
- responsible for thermoregulation, osmoregulation, hunger, thirst, fatigue
pituitary gland?
• consists of anterior and posterior pituitary
medulla oblongata?
- lower portion of the brain stem, just b4 SC
- responsible for autonomic functions lik BP and breathing
- contains cardiac centre = responsible for controlling HR
anterior pititary?
- neurosecretory cells secrete growth hormone releasing factor
- GHRF causes endocrine cells to secrete GH
Posterior pituitary?
- osmoreceptors detect low blood WP and activate neurosecretory cells
- neurosecretory cells secrete ADH
Neurons in CNS?
relay
Neurons in Peripheral NS?
SN & MN
Somatic NS
input from sense organs, output to skeletal muscles
Autonomic NS
input from internal receptors, output to SM and glands
Sympathetic NS NT?
noradrenaline
Parasympathetic NS NT?
Ach
Adrenaline release (somatic NS)
- Adrenal medulla releases adrenaline
- stimulated by envir stimulus
- adrenaline causes fight/ flight
- Amplification cascade caused by cAMP
Amplification cascade?
millions of glucose molecules made from glycogen instantaneously
Fight or flight response
- Respiration rate inc
- causes blood pH to decrease (carbonic acid dissociates)
- causing acidosis
- so rate of CO2 excretion must inc
- HR increases to inc CO2 delivery to lungs
- this would raise blood pH back to normal
Control of HR: Medulla contains
- cardio acceleratory centre
* cardioinhibtory centre
cardioacceleratory centre is connected to SAN via?
accelerator nerve
cardioinhibitory centre is connected to SAN via?
vagus nerve
Baroreceptors?
- detect pressure changes in aorta and carotid arteries
- if pressure is high CI stimulated
- if low CA stimulated
Accelerator nerve?
increases HR
Vagus nerve?
decreases HR
The cardiac centre?
controls HR, contains CIC and CAC
What do chemoreceptors do?
- monitor blood pH
- Too high = CI stimulated
- too low = CA stimulated
If HR ⬇?
- BP and pH decrease
- detected by baroreceptors and chemoreceptors
- CAC activated
- APs move along accelerator nerve
- noradrenaline released at SAN
- HR ⬆, adrenaline sec ⬆
if HR is too ⬆?
- pH too high as CO2 excretion too high
- baroreceptors and chemoreceptors
- CIC activated, APs along vagus nerve
- ACh released at SAN
- HR and adrenaline secretion decreases
nervous and hormonal communication of HR is an e.g. of
negative feedback
Sarco =
flesh
What needs to occur before a muscle can contract?
myosin binding sites need to be exposed
NMJ?
a synapse between a MN and muscle fibre
Types of muscle?
skeletal, smooth, cardiac
Skeletal muscle?
- attaches skeleton
* only contract w stim from MN
smooth muscle?
- arteries, bronchi, airways
- all BC other than capillaries
- any BV that is not attached to a skeleton
cardiac muscle?
heart
which types of muscle are striated?
skeletal and cardiac
what is a muscle fibre called?
syncytium
SM is ran entirely by _____ NS?
autonomic
When muscles contract?
end up exerting a force on the bone, so we end up pulling on body parts
Muscles in the upper arm?
- 2 main
- when the bicep contracts it pulls the radius and ulna towards the scapular bending the arm
- at the same time, the tricep muscle lengthens
- when the tricep contracts, the arm straightens - extensor muscle
- an antagonistic pair
- so we have controlled moment
muscles always work in ?
pairs
each muscle fibre?
lies parallel to one another
muscle fibres can ? but we can’t make more muscle
swell
structure of a muscle fibre?
- lots of cells where the PM has broken down between them, leading to a giant multinucleated cell
- these syncytium are surrounded by a specialised plasma membrane called the sarcolemma
- many mitochondria
- lots of SER - called sarcoplasmic reticulum
longitudinal stripes in a muscle fibre are called ?
myofibrils. Around these are organelles pushed to the edges
what are the invaginations of the sarcolemma called?
T tubules
sarcoplasm?
cytoplasm of muscle cell- not v much
actin appearance on micrograph?
thin, appears lighter
A band ?
myosin + interlocking actin
I band?
actin only
H band ?
where there is only myosin - no actin
Z line to Z line
anchor of actin
M line ?
anchor of myosin
one complete unit/sarcomere ?
Z line to Z line
When muscles contract,
they slide over each other and get shorter - I band
