Animal Response Flashcards
What does the human nervous system consist of?
Central nervous system (CNS) – the brain and the spinal cord
Peripheral nervous system (PNS) – all of the nerves in the body
What 2 parts can the nervous system be divided into?
The somatic nervous system - voluntary
The autonomic nervous system - involuntary
What are the 3 types of nerves in the somatic nervous system?
Sensory nerves - these consist of sensory neurones and carry impulses from sense organs to the CNS
Motor nerves - the consist of motor neurones and carry impulses from the CNS to muscles and glands
Spinal nerves - found in the spinal cord, these are mixed nerves that consist of both sensory and motor neurones
What are the 2 parts of the autonomic nervous system?
The sympathetic nervous system, which controls ‘flight-or-fight’ responses
The parasympathetic nervous system, which controls the ‘rest and digest’ system
How is the flight-or-fight response controlled by the sympathetic nervous system?
The sympathetic nervous system controls the release of adrenaline in the adrenal gland
It causes the heart rate to increase
increase in blood supply to muscles so they have more oxygen and glucose for respiration
It enables high-intensity activities to be an immediate response
What are the regions in the brain?
Cerebrum
Hypothalamus
Pituitary gland
cerebellum
Medulla oblongata
What are the functions of the cerebrum?
Controls voluntary actions
- Thought
- vision
- speech
- memory
- problem solving
What are the functions of the cerebellum?
Responsible for muscle coordination and movement
What are the functions of the Hypothalamus?
Control centre that monitors blood and helps maintain homeostasis
What are the functions of the Medulla oblongata?
Controls involuntary actions
e.g heart rate and breathing
What are the functions of the pituitary gland?
Responsible for regulating many body functions, controlling the activity of glands
What are reflexes?
Rapid, unconscious actions that protect the body from harm.
They avoid the conscious part of the brain
Explain the knee-jerk response
Stretch receptors in the quadriceps muscles detect that the muscle is being stretched
an electrical impulse is sent along a sensory neuron to the spinal cord
the impulses is passed on to a motor neuron which carries the impulse to the quadriceps muscle.
the muscle contracts and causes the leg to straighten
How is the nervous system used to prepare for flight or flight?
Sympathetic branch of the autonomic nervous system is activated which sends signals to adrenal glands to release adrenaline
How is the hormonal system used to prepare for flight or flight?
Pituitary gland releases ACTH which stimulates release of steroid hormones from adrenal cortex
What are the effects of adrenaline on the body?
Stimulate breakdown of glycogen in glucose (glycogenolysis)
Directs blood flow away from digestive system towards muscles and the brain
Increases heart rate and breathing
erector pili muscles in the skin contract and hairs stand on end
How does the cardiovascular control centre change heart rate?
sends impulses along the sympathetic or parasympathetic neurones which release different neurotransmitters onto the SAN
SAN modifies its firing rate to slow or speed up the heart rate
What are the 2 types of receptors?
Animal response
Baroreceptors (Pressure receptors) - detect changes in blood pressure and are found in the aorta and carotid artery
Chemoreceptors (Chemical receptors) - detect concentration of oxygen in the blood and pH levels and are found in the aorta and carotid artery
How does our body respond to low blood pressure or oxygen levels?
the baroreceptors and chemoreceptors in the aorta and carotid artery detect that blood pressure and O2 levels are low
Impulse sent along the sensory neuron to the cardiovascular control centre
This activates the sympathetic nervous system which releases noradrenaline
Noradrenaline binds to the SAN, causing it to increase firing rate
How does our body respond to high blood pressure or oxygen levels?
the baroreceptors and chemoreceptors in the aorta and carotid artery detect that blood pressure and O2 levels are high
Impulse sent along the sensory neuron to the cardiovascular control centre
This activates the parasympathetic nervous system which releases acetylcholine
Acetylecholine binds to the SAN, causing it to decrease firing rate
What are the 3 types of muscle?
Skeletal muscle
cardiac muscle
smooth muscle
Describe the structure of skeletal muscle?
Made of bundles of muscle fibres
Cell membrane called sarcolemma, cytoplasm called sarcoplasm
Sarcolemma folds into the sarcoplasm to fomr transverse tubules
Contain a sarcoplasmic reticulum which stores calcium ions
Multinucleated
Contain myofibrils
What are myofibrils?
Long cylinders of proteins which enable the muscle fibre to contract
Made of many sarcomeres which are made of actin and myosin
Describe the structure of a sarcomere
Myosin - thick filaments, dark bands
Actin - thin filament, ligh bands
I band - only actin
A band - all the myosin including the overlapped actin
Z-line - at the end of each sarcomere
M-line - the middle of the sarcomere
H-Zone - only myosin
What happens during muscle contraction?
Myosin and actin filaments more closer together by sliding over one another.
Filaments stay the same size
H band shortens
I band shortens
A band stays the same (more actin)
Sarcomere shortens and they contract
Explain the sliding filament model
(formation of actin-myosin bridge)
Myosin contains heads which contain binding sites for actin and ATP.
The actin-myosin binding site is blocked in resting conditions by tropomyosin and troponin
an action potential passes down the t-tubules and causes the release of Ca2+ ions from the sarcoplasmic reticulum
calcium ions bind to troponin which changes its shape and pulls the tropomyosin out of the actin-myosin binding site
myosin head can bind to actin to form a actin myosin-cross bridge
Explain the sliding filament model
(After actin-myosin cross bridge)
The release of calcium ions activates ATPase which catalyses ATP to ADP + Pi
The energy produced is used by myosin heads to bend. This is known as the power stroke
Energy from ATP breaks the actin-myosin bridge and the myosin head can reattach to a binding site further along the actin filament
What happens when the muscle is not stimulated?
Ca2+ ions move back into sarcoplasmic reticulum by active transport
Troponin and tropomyosin molecules return to blocking actin-myosin binding site
Sarcomere lengthens
What are the 3 sources of ATP?
Aerobic respiration
Anaerobic respiration
Phosphocreatine
How does ATP-creatine phosphate system produce ATP?
ADP + CP = ATP + C
Creatine phosphate is stored inside of cells and produces ATP very quickly
Anaerobic
What happens at a neuromuscular junction?
Action potential arrives which stimulates the release of Ca2+
Ca2+ causes acetylcholine to fuse with presynaptic membrane and diffuse across synaptic cleft
Acetylcholine binds with the receptors on the sarcolemma which opens Na+ ion channels and Na enters the sarcolemma and the membrane depolarises
