ANIMAL RESPONSES Flashcards
Function of cerebrum
Largest part of human brain
Responsible for elements of the nervous system (e.g. conscious thoughts, imagination)
2 hemispheres, joined by corpus collosum
Function of cerebellum
Folded surface smaller than cerebrum
Contains over half of the nerve cells in the brain
Responsible for coordination, balance
Processes sensory information from retina, joints + spindle fibres
Function of medulla oblongata
Links brain + spinal cord
Controls non-skleletol muscles
Therefore coordinates + controls involuntary movements such as breathing + heart rate
Controls cycles (e.g. respiratory)
Function of hypothalamus
Main control system of autonomic nervous system
Receives sensory input from temperature receptors + osmoreceptors
Initiates automatic responses to regulate temperature and blood water potential
Regulates pituitary gland
Function of pituitary gland
Posterior lobe linked by hypothalamus
Anterior pituitary gland produces six hormones (e.g. FSH)
Posterior pituitary stores + releases hormones produced by hypothalamus (e.g. ADH)
Function, target tissues + effect, number of neurones (myelinated or not) of somatic neurone
Controls conscious activities (e.g. movements, reflexes)
Skeletal muscles
Excitatory- muscle contract
One, myelinated
Function, target tissues + effect, number of neurones (myelinated or not) of autonomic neurone
Controls homeostasis and mechanisms, regulates internal organs
Smooth and cardiac muscles (+ some glands)
Excitatory or inhibitory- muscle contracts
2 (linked by ganglion outside spinal cord)
Mostly non-myelinated
Compare the functions of sympathetic and parasympathetic nervous system
Parasympathetic more active during sleep and relaxation
Sympathetic more active at times of stress
Have antagonistic effects
Structure comparison sympathetic and parasympathetic
Position of ganglion
Length of pre-ganglionic neurone
NT
Outside spinal cord, within target tissue
V short, varies
Noradrenaline, ACH
Neuromuscular junctions
- AP causes v-gated Ca2+ channels to open, Ca2+ diffuses in
- Ca2+ causes synaptic vesicle to move + fuse with the presynaptic membrane + release ACH into cleft (exocytosis)
- ACH diffuses across cleft + binds to receptors on sarcolemma= Na+ open
- Na+ floods in= depolarisation down t-tubules
- CA2+ channels open + diffuse out sarcoplasmic reticulum
- Ca2+ binds with proteins in muscles= contraction
- Acetylcholinesterase breaks down ACH so contraction only occurs with an impulse
What is a reflex
Rapid + involuntary
Process of a reflex
Stimulus detected by receptor
Impulse- sensory- spinal cord
Either passes directly to the motor neurone or to a relay then motor
If relay- synapses with other CNS neurones= consisted awareness
Blinking reflex
- sensory neurone from cornea seeds impulse to brains stem
- synapse with unmyelinated relay neurones
- motor cause facial muscles to contract= blink
Knee jerk reflex
- patella tendon stretches, stretch receptors detect change in length
- sensory neurone stimulates motor
- extensor muscle contracts + straightens leg
- at the same time- impulse from sensory- relay= relaxes flexor muscle
Fight or flight response
Physiological changes
Increased HR
Pupils dilate
Erector pili muscles in skin contract
Ventilation and depth increases
Cascade effect
- stimulus (visual/auditory)
- cerebral understands threat= activate hypothalamus
- increased activity in sympathetic nervous system
- adrenaline released
- anterior pituitary gland releases adreno-corticotrophic hormone
- stimulates production go cortisol
- cortisol releases glucose
SAN/pacemaker
Controls HR at rest
Initiates AP
Excitation travels over atrial walls, through AVN, down purine tissue to the ventricles= contraction
Nervous control
Stretch receptors
Baroreceptor
Chemoreceptor
Sensory neurone sends message to cardiovascular centre
Stretch receptor in muscles- detect movement of limbs, indicates increased O2 will be needed (increase HR)
Baroreceptor- in carotid artery (aorta, vena cava)- detects changes in pressure
Chemo- brain, aorta, detect change sin pH- reduced pH= increased CO2= increase HR
Hormonal control
Adrenaline binds to receptors in cardiac muscles, increases force + rate of HR
Voluntary (skeleton muscles)
Striated bands of actin + myosin
Cylindrical
Multinucleate
Found in limbs + intercostal muscles
Moves bones at joints
Involuntary (smooth)
Non striated
Uninucleate
Bronchi, bronchioles, arteries, arterioles, gut, oesophagus
Controls diameter of above
Cardiac muscles
Striated
Branched
Uninucleate
In heart
Pumps blood around the body
Skeletol muscle structure
Thousands of muscle fibres Surrounded by sarcolemma (cell mem) with many deep foldings (t-tubules) Sarcoplasm- contains mitochondria Sarcoplasmic reticulum Myofibrils- myosin + actin
Thick myosin filaments
Bundles of fibrous proteins
Myosin tail attached to M-line + a head
Heads point away from M-line
Thin actin filaments
Two heliacal strands of globular proteins
Coiled around fibrous proteins= tropomyosin
Attached at regular intervals to tropomyosin + actin
Muscle contraction sequence
- impulse= Ca2+ being released into sarcoplasm
- bind to troponin causing it to change shape
- moves tropomyosin + exposes binding sites
- myosin heads attach forming cross bridges, they end to create a power stroke
- ATP attacks to the myosin heads causing them to detach from biding sites, hydrolysed to form ADP + Pi
- myosin heads attach to new binding sites
ATP for muscle contraction
ATP= immediate energy source
Creatine phosphate= held with muscle sarcoplasm + creates ATP
Blood= oxygen + glucose for aerobic
Glycogen reserves found in muscle fibres + oxygen in oxymyoglobin
Anaerobic= casques arctic acid build up
Electromyograph
Small electric signal cane detected through electrodes placed on skin surface
How does the parasympathetic nervous system conserve energy
- slows heart rate- less energy used for muscle contraction
- reduces force of heart rate- less energy for muscle contraction
- breathing rate reduced- diaphragm and intercostal muscles relax
What happens after myosin heads are detached from binding sites
Hydrolysis of ATP (ATP–> ADP + Pi) needed for myosin head to return to original position
How do neurotransmitters move through cleft
Via microtubules
Synthesis of proteins allows for what
Repair and growth
What is used to hydrolyse ATP into ADP
Creatine phosphate
