Animal Responses(Brain + Muscles) - Module 5 Flashcards
Frontal Lobe
Frontal Lobe – concerned with higher brain functions such as decision making, reasoning, planning and consciousness of emotions. It includes the motor cortex which stores information about how to carry out different movements.
Parietal lobe
Parietal lobe – concerned with orientation, movement, sensation, calculation and types of recognition and memory.
Occipital lobe
. Occipital lobe – Visual cortex, concerned with processing information from the eyes including vision, colour, shape and perspecive.
Cerebellum –
coordinates muscular movement
balance + Posture
Temporal Lobe
Temporal Lobe – concerned with processing auditory information i.e. Hearing, sound, recognition of speech. Also involved in memory.
Cerebrum
2 hemispheres
-Controls voluntary action
-personality
-learning
-memory
-conscious thoughts
Coordinated Movement - cerebellum
Fine control of muscular movements e.g. walking, requires significant level of nonconscious operation.
Neurones from cerebellum carry impulses to motor areas so effectors can be adjusted appropriately – autopilot.
Hypothalamus
monitors our internal environment via hormones and or nervous impulse
Monitoring composition of blood plasma (concentration of water and blood glucose)
Main control of the autonomic nervous system (functions of organs etc.)
control endocrine glands.
Two centres – parasympathetic and sympathetic
Controls complex patterns of behaviour (feeding, sleeping, aggression) depending on environment
Producing hormones
Medulla Oblongata
AUTONOMIC CONTROL
Controls action of smooth muscle in gut wall and controls breathing movements as well as heart rate.
Controls reflex activities (ventilation, heart rate)
Controls swallowing, peristalsis and coughing
Pituitary Gland
Found at the Base of the hypothalamus. t controls most of glands in body. Divided into two sections:
Anterior pituitary (front section) -
Posterior pituitary (back section) -
Anterior pituitary
(front section)- produces six hormones including follicle – stimulating hormone (FSH), which is involved in reproduction and growth hormones
Posterior pituitary
(back section) - stores and releases hormones produced by hypothalamus, such as ADH involved in urine production
CNS
brain and spinal chord
relay neurones
Peripheral nervous system
3 components
everything other than CNS
-receptors
-sensory neurones
-Motor Nuerones
Sensory neurones
from receptors
Motor neurones
to effector
Somatic motor neurone
CNS to skeletal muscle – (conscious control, voluntary) (myelinated)
Autonomic motor neurone
Autonomic motor neurone (CNS to cardiac muscle, smooth muscle in gut and glands – not under voluntary control)
(2 types sympathetic and parasympathetic) (non-myelinated)
Peripheral nervous system splits into …
– two different systems: somatic and autonomic nervous systems
Somatic nervous system
– controls conscious activities
Autonomic nervous system
controls unconscious activities.
Split up in to sympathetic and parasympathetic systems (have opposite effects)
Sympathetic nervous system
Increases activity
“fight or flight” system, releases noradrenaline
Parasympathetic nervous system
Reduces activity
“rest and digest” system,
releases Acetylcholine
What does high conc. of CO2 do to pH
why
= increase in carbonic acid = increase H ions = Decrease pH
The heart rate changes depending on ..
Blood pressure, pH of Blood, Stress response
what is blood pressure detected by
what do they do in response to this
Blood pressure is detected by baroreceptors
Baroreceptors send nerve impulses along sensory neurones to the cardioregulatory centres in the medulla oblongata.
Where are Baroreceptors and chemoreceptors found
in the aorta and carotid artery.
If BP is too low the cardiovascular centre sends impulses…
Neurones secrete …
If BP is too low the cardiovascular centre sends nerve impulses along the sympathetic neurones to the SAN to increase heart rate.
Neurones secrete noradrenaline which binds to receptors on SAN.
High blood pH (high O2, low CO2)
Chemoreceptors detect changes and send impulses along sensory neurones to cardiovascular centre.
Impulse sent along parasympathetic neurones.
These secrete acetylcholine which bind receptors on SAN.
Decreases heart rate.
Low blood pH (low O2, high CO2)
Chemoreceptors detect changes and send impulses along sensory neurones to cardiovascular centre.
Impulse sent along sympathetic neurones.
These secrete noradrenaline which bind receptors on SAN.
Increases heart rate.
the medulla oblongata splits into which two cardioregulatory centres
cardiostimulatory centre
Cardioinhibitory centre
If pH is too high or Blood pressure is too high, how is the heart rate controlled
Chemo or baroreceptors detect these changes.
send impulse to Medulla Oblongata
to cardioinhibitory centre.
Cardioinhibitory centre triggered to send impulse along Vagus nerve. Releases acetylcholine. bind to SAN which reduces heart rate
If pH is too low or Blood pressure is too low, how is the heart rate controlled
Chemo or baroreceptors detect these changes.
send impulse to Medulla Oblongata
to cardiostimulatory centre.
Cardiostimulatory centre triggered to send impulse along accelerator nerve to SAN which increases heart rate
How do hormonmes controll the heart rate
Adrenal medulla releases Adrenaline and Noradrenaline which bind directly to SAN and to increase frequency of signals released
Sarcoplasm
Sarcoplasm- A muscle cell’s cytoplasm. Lots of mitochondria are found within the sarcoplasm
Sarcolemma
Sarcolemma- cell membrane of muscle fibres.
Transverse (T) tubules
Transverse (T) tubules- Folds in the sarcolemma that stick into the sarcoplasm. Help to spread electrical impulses throughout sarcoplasm
sarcoplasmic reticulum
Sarcoplasmic reticulum- A network of internal membranes that store and release calcium ions needed for muscle contraction
Myofibrils
Myofibrils- Long, cylindrical organelles made of protein within a muscle fibre that are highly specialised for contraction
Myofibrils
Each muscle contains lots of these
Long cylindrical organelles made of protein and specialised for contraction
Collectively very powerful
Made of 2 protein filaments:
- actin
-Myosin
Made up of many sarcomeres
The sliding filament model
Muscle contraction is explained by the sliding filament model- when myosin and actin filaments slide over each other to make the sarcomere contract.
Simultaneous contraction of lots of sarcomeres means the myofibrils and muscle fibres contract
Sarcomeres return to their original length when the muscle relaxes.
At its resting state, what is bound to the myosin head?
ADP
THE EFFECT OF CHEMICALS ON MUSCLE CONTRACTION
sometimes a chemical may block the release of the neurotransmitter or affect the way it binds to receptors on the postsynaptic membrane. This may prevent the action potential from being passed on to the muscle, so the muscle won’t contract
what is Pancuronium bromide
non-depolarising, neuromuscular blocking drug. Competes against ACh for the nicotinic cholinergic receptors, binding to them so that the action of ACh is blocked and t he muscle cell does not depolarise. IT is used during surgery as it relaxes muscles.
How to reverse the action of pancuronium bromide
inhibit action of AChE so that the concentration of ACh increases. This means that it can out compete the drug for available nicotinic cholinergic receptors
where does energy for muscle contraction come from
1) Aerobic respiration
2)Anaerobic respiration
3) ATP-Creatine phosphate
What is ATP-Creatine phosphate
How is it made
ATP made by phosphorylating ADP, Pi from Creatine phosphate(CP) . CP stored inside cells. CP runs out after a few seconds. Used in short bursts during vigorous exercise. Anaerobic system, Doesn’t make lactate
Proteins present in A band
Myosin and Actin
Proteins present in H zone
Myosin
Proteins present in I band
Actin
Proteins present in Z line
Actin
Proteins present in Z line
Actin
Proteins present in Sarcomere
Myosin, Actin
Proteins present in M line
Myosin
actin
- actin: thinner filament, 2 strands twisted
myosin
: thicker filament, long rod-shaped fibres with bulbous heads
what happens during contraction to A band
stays same
what happens during contraction to H zone
gets shorter
what happens during contraction to I band
Gets shorter
what happens during contraction to Z line
Get closer together
what happens during contraction to Sarcomere
gets shorter
what happens during contraction to M line
stays the same
what is the H zone
Zone that contains myosin only within A band
what is a Z line
The ends of each sarcomere are marked with a Z line
what does skeletal muscle control
Conscious movements
what does smooth muscle control
unconscious movement
what does cardiac muscle control
Involuntary movement
where is smooth muscle located
in walls of hollow internal organs
e.g: gut, blood vessels, bladder
where is cardiac muscle located
walls of heart
length of fibres of skeletal muscle
can be many centimeters long
length of fibres of smooth muscle
approx 0.2 mm
length of fibres of cardiac muscle
approx 0.1 mm
Shape of muscle fibres in skeletal muscle
Tubular
Shape of muscle fibres in smooth muscle
Spindle shaped with pointed ends
Shape of muscle fibres in cardiac muscle
Branched cylinders connected by intercalated disks
number of nuclei of skeletal muscle
multinucleate
number of nuclei of smooth muscle
uninucleate
number of nuclei of cardiac muscle
uninucleate
are the cross striations visible under light microscopes in skeletal muscle fibres
yes
are the cross striations visible under light microscopes in smooth muscle fibres
no
are the cross striations visible under light microscopes in cardiac muscle fibres
some, not as strong
Length and speed of contraction of skeletal muscle
-Short - contract quick and fatigue quick
-long - contract and fatigue slowly. usually for endurance and posture
Length and speed of contraction of smooth muscle
Contract slowly and don’t fatigue
Length and speed of contraction of cardiac muscle
Contract rhythmically and don’t fatigue
outline effects of sympathetic and parasympathetic NS on resting heart rate
(3mrk)
-sympathetic increases heart rate
-parasympathetic slows heart rate
-idea that parasympathetic is dominant at rest
Knee-jerk reflex process
1)Tap under kneecap causes patellar tendon to stretch, also stretches extensor muscle
2)Sends reflex arc impulse through sensory neurone
3)Reflex signal goes along one motor neurone, causing Extensor muscle to contract
4)Relay Neurone inhibits the other motor neurone of flexor muscle -> Relax
5)Leg kicks due to antagonistic muscle action
(is an example of a spinal reflex)
what is a cranial reflex
(involves the brain)
Blinking reflex process
1)Cornea irritated
2)Triggers impulse along sensory neurone
3)Relay neurone in Lower brain stem Passes impulse along
4)Signal branches off in motor neurone to eyelid muscles
5)Both eyes shut as a consensual response
why are reflexes important for survival
Reflexes are involuntary actions , prevents overloading
are innate
are extremely fast
Some are everyday actions e.g: blinking
How is the blinking reflex used by doctors
Used to assess whether a patient is braindead (brain stem is functioning or not)a
as it is a cranial reflex
the relay neurone involved exists in the lower brain stem. So if lower brain stem is functioning, blinking reflex still occurs
Mechanisms of sliding filament model -> STIMULATION
1) An action potential from a motor neurone depolarises the sarcolemma-
2) this spreads down the T tubules to the sarcoplasmic reticulum.
3) The sarcoplasmic reticulum voltage gated calcium ion channels open
4) The sarcoplasmic reticulum releases stored calcium ions into the sarcoplasm. Ca2+ diffuses through sarcoplasm
5) The calcium ions bind to troponin which causes it to change shape.
6) This pulls the attached tropomyosin out of the actin-myosin binding site on the actin filament. the binding site is exposed
Attachment stage of muscle contraction
- As the binding site is exposed, the myosin head can bind forming an actin-myosin cross bridge.
- (Binding causes) Myosin filament flexes, pulls actin along
- (Binding causes) releases ADP
Detachment stage of muscle contraction
- ATP now binds to Myosin head (as ADP was just released).
- Changes conformational shape. so that Myosin head Detaches from actin myosin binding site
- Calcium ions bind to myosin head and activate the enzyme ATPase which hydrolyses ATP to ADP + Pi
- Energy released returns myosin head to original position
- Myosin head attaches to next A-M binding site.
- process repeats
When the muscle stops being stimulated…..
When the muscle stops being stimulated, calcium ions leave their binding sites on the troponin molecules and are moved back to the sarcoplasmic reticulum by active transport.
The troponin molecules move back to their original shape, pulling the attached tropomyosin molecules with them. This blocks the actin-myosin binding sites again.
