Animal Responses Flashcards
What is a stimulus?
A change in the environment that requires a response
What is an effector?
A muscle/gland that responds to a stimulus
Where are thermoreceptors located?
Hypothalamus and skin (peripheral)
How do thermoreceptors relay information about temperature to the hypothalamus?
Nerve impulses
How does the hypothalamus cause a response in effectors?
Action potential
What are the 2 systems in the nervous system?
Central nervous system
Peripheral nervous system
What are the 2 parts of the central nervous system?
Brain
Spinal cord
What are the 2 parts of the peripheral nervous system?
Autonomic (involuntary responses)
Somatic (voluntary movements)
What are the 2 parts of the autonomic nervous system?
Sympathetic - excitatory effect
Parasympathetic - inhibitory effect
What are the effectors in the somatic compared to the autonomic nervous system?
Somatic - Skeletal muscles
Autonomic - Cardiac/smooth muscle/glands
How is the brain involved in the somatic compared to the autonomic nervous system?
Somatic - Always involves the brain cerebral hemispheres
Autonomic - Doesn’t always involve the brain
How much is thought involved in the somatic compared to the autonomic nervous system?
Somatic - Involves conscious thought
Autonomic - Occurs without thought
How is the neural networks different in the somatic compared to the autonomic nervous system?
Somatic - Involves complex neural networks
Autonomic - Simple nerve pathways, involving few neurones
How is the myelin different in the somatic compared to the autonomic nervous system?
Somatic - Most neurones myelinated
Autonomic - Most neurones are non-myelinated
How are the connection different in the somatic compared to the autonomic nervous system?
Somatic - Connections to effectors consist of one neurone
Autonomic - Connections to effectors always consist of at least 2 neurones that connect at a ganglion
How is the region of the CNS different in the sympathetic compared to the parasympathetic nervous system?
Sympathetic - Thoracolumbar region (spine)
Parasympathetic - Craniosacral region (brain/bottom of spine)
How is the location of the ganglion different in the sympathetic compared to the parasympathetic nervous system?
Sympathetic - Close to spinal cord
Parasympathetic - Close to target organs
How is the length of the post ganglionic fibres different in the sympathetic compared to the parasympathetic nervous system?
Sympathetic - Long
Parasympathetic - Short
How is the post ganglionic branching different in the sympathetic compared to the parasympathetic nervous system?
Sympathetic - Lots - multiple organs mobilised at once
Parasympathetic - Very little
What neurotransmitter is used in the sympathetic compared to the parasympathetic nervous system?
Sympathetic - noradrenaline
Parasympathetic - acetylcholine
What is the function of the cerebrum?
Controls voluntary actions such as, learning, memory, personality, and conscious thought.
What is the function of the cerebellum?
Controls unconscious functions such as posture, balance and non-voluntary movements
What is the function of the medulla oblongata?
Used in autonomic control eg controlling heart and breathing rate
What is the function of the hypothalamus?
Regulatory centre for temperature and water balance
What is the function of the pituitary gland?
Stores and releases hormones that regulate many body functions
Are reflexes learned or natural?
It is an innate behaviour determined by inherited nervous pathways.
What are the parts of a reflex arc?
Stimulus, receptor, sensory neurone, dorsal route, white matter, grey matter, interneuron/relay neurone, ventral route, motor neurone and effector
Why are reflexes important?
Protect the body from harmful stimuli
What is a dorsal root ganglia?
Contains all cell bodies of sensory neurones
What is a motor end plate?
Transfer impulse to effector organ
What is a grey matter?
Made up of motor nerve cell bodies and relay neurones
What is a spinal nerve?
Made up of long nerve fibres running the length of the spinal cord
What is a dorsal root?
Carries only sensory nerve fibres from spinal nerve into spinal cord
What is a white matter?
These are mixed nerves carrying both motor and sensory fibres. They are attached to the spinal cord by dorsal and ventral roots
What is a ventral root?
Carries only motor nerve fibres from spinal cord into spinal nerve.
What is a reflex action?
An innate, involuntary, automatic response to a stimulus.
They occur quickly as no thought is involved and they occur to protect the body from harmful stimuli.
What do baroreceptors detect?
Change in blood pressure
What do chemoreceptors detect?
Change in pH
What is the structure of skeletal muscle?
Striated Multi-nucleate Long muscle fibres made of many muscle cells joined together Under voluntary control Allows movement of the skeleton Can be fast or slow twitch fibres Fatigue
What is the structure of smooth muscle?
Smooth Single nucleus Small, spindle-shaped muscle cells Controls bp and peristalsis Under involuntary control Surrounds hollow internal organs Contract slowly and don't fatigue
What is the structure of cardiac muscle?
Partially striated single nucleus Small, cylindrical-shaped muscle cells Branched with intercalated disks Myogenic Found only in walls of the heart Contract rhythmically and don't fatigue
What is the sarcolemma?
Cell membrane of muscle cell fibres
What is the sarcoplasm?
Cytoplasm of muscle cell fibres
What are T tubules?
Inward foldings of the sarcolemma, projecting into the sarcoplasm. They help to spread electrical impulses throughout the sarcoplasm
What is sarcoplasmic reticulum?
Specialised ER. A network of internal membranes running through the cytoplasm that stores and releases calcium ions needed for muscle contraction.
What does multi-nucleate mean?
Contain many nuclei. Made by cells placed end to end and specialised to form long muscle fibres (cells)
What are myofibrils?
Long cylindrical organelles composed of specialised contractile proteins (actin and myosin) required for muscle contraction
Which band stays the same width during contraction?
A band
Which parts of a myofibril shorten during contraction?
H zone
I band
What blocks the binding site on the actin?
Troponin and tropomysosin
How is troponin/tropomyosin moved from the binding site on the actin?
When the muscle is stimulated, calcium ions are released from the sarcoplasmic reticulum which causes tropomyosin to change shape and move away from the binding sites on the actin.
What does the myosin head do when the tropomyosin has moved away from the binding sites on the actin?
Myosin head binds to the actin.
What does the myosin do once it is attached to actin?
Changes angle, moving actin filament along as it does so ADP molecule is released. This is called the power stroke. The Sarcomere shortens.
What happens after the power stroke?
ATP molecule fixes to myosin head causing it to detach from the actin filament.
Hydrolysis of ATP by myosin provides the energy for the myosin head to resume its normal position.
The myosin head can repeat the cycle further along the actin filament.
How is an action potential generated in the sarcolemma?
An action potential reaches an axon terminal / neuromuscular junction.
Acetylcholine is released, diffuses across the synaptic cleft and attaches to receptors on the sarcolemma.
Na+ channels open and Na+ move in creating an action potential in sarcolemma.
What happens to the action potential in the sarcolemma?
It is propagated along the sarcolemma and down the T tubules.
What does the action potential in the T tubules cause?
Triggers release of Calcium ions from sarcoplasmic reticulum.
What do the calcium ions released from the sarcoplasmic reticulum do?
Bind to troponin/tropomyosin and change their shape to remove them from the actin active sites.
Word equation for aerobic respiration?
Glucose + Oxygen -> Carbon dioxide + Water
What is oxygen debt?
As anaerobic respiration occurs, lactate builds up. After exercise it is the amount of oxygen consumed by the lactate that is extra to the normal oxygen requirements at that metabolism.
How long does the PC system last?
10 seconds
What is the equation for the PC system?
PC + ADP -> C + ATP
