Animal Response Flashcards
(29 cards)
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, subconscious
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
what is the mechanism for fight or flight response?
Autonomic nervous system detects a threat and sends an impulse to the hypothalamus
Hypothalamus activates the sympathetic nervous system
Sympathetic nervous system sends nerve signals to the adrenal glands which triggers the release of adrenaline and noradrenaline
This stimulates the hypothalamus to release ACTH
Explain adrenaline in the secondary messanger
Adrenaline attaches to receptors on the surface of target cell
G protein is activates adenylyl cyclase which catalyzes ATP
to cAMP
cAMP acts as a secondary messenger
cAMP binds to protein Kinases which activates an enzyme that catalyzes the breakdown of glycogen to glucose for respiration
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, automatic response that protects 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
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
Airway muscles relax
What are the 2 types of receptors involved in controlling heart rate?
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
Heart rate increases
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 center
This activates the parasympathetic nervous system which releases acetylcholine
Acetylcholine binds to the SAN, causing it to decrease firing rate
Heart rate decreases
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
