ANIMAL RESPONSES Flashcards
The autonomic system controls involuntary responses using effectors (muscles or glands).
A preganglionic neuron originating in the CNS connects to an autonomic ganglion.
The autonomic ganglion is then connected to an effector by a postganglionic neuron, so there are two neurons outside the CNS.
Cerebrum:
Frontal lobe
Emotions, reasoning, problem solving and planning
Temporal lobe
Auditory processing, language and memory
Occipital lobe
Visual processing
Parietal lobe
Integration of sensory information
The fight or flight response involves both the nervous system and the endocrine system.
The release of stress hormones adrenaline and cortisol increase the length of time for which the organs are affected.
n the sympathetic nervous system, preganglionic nerves release acetylcholine at synapses. At the synapses between postganglionic nerves and effectors, norepinephrine is released, which binds with adrenergic receptors.
reflex arc
Thermoreceptors in the skin detect the heat stimulus.
Sensory neurone carries impulse from thermoreceptors to relay neurone in the spinal cord.
Relay neurone carries impulse to motor neurone.
Motor neurone carries impulse to effectors (muscles in arm).
Arm moves away from hot object.
he waves of electrical activity cannot pass from the atria to the ventricles due to a collection of non-conducting tissue.
This creates a delay to ensure the atria are empty before the ventricles begin to contract.
The electrical activity passes through the AVN to the bundle of His.
The bundle of His is a collection of conducting tissue that transmits the electrical activity to the apex (bottom) of the heart and around the ventricle walls along fibres called the Purkyne fibres.
There are two main receptors involved in controlling heart rate: chemoreceptors and baroreceptors. When stimulated these receptors send a signal to a region in the brain called the medulla oblongata.
Chemoreceptors
Sensitive to changes in CO2 concentration.
If CO2 concentration is high, heart rate increases.
Found in the aortic body, in the wall of the aorta.
Found in the carotid body, in the wall of the carotid artery in the neck.
Baroreceptors
Sensitive to changes in blood pressure.
If blood pressure increases, heart rate decreases.
Found in the walls of various arteries but particularly in the carotid sinus (in the wall of the carotid artery).
Medulla oblongata
When stimulated, chemoreceptors and baroreceptors send a signal to a region in the brain called the medulla oblongata.
The region in the medulla which modifies heart rate is the cardiovascular centre.
The cardiovascular centre has two regions:
Cardio-inhibitory centre.
Cardio-acceleratory centre.
Nervous impulses are sent from these centres along the autonomic nervous system to the sinoatrial node (SAN).
Skeletal muscle consists of many bundles of muscle fibres.
Muscle fibres are long, specialised cells.
The membrane of muscle fibres is called the sarcolemma.
The sarcolemma folds inwards to the sarcoplasm (muscle fibre cytoplasm) at certain points.
The inwards folds are called transverse (T) tubules. The tubules are very important in initiating muscle contraction.
The sarcoplasmic reticulum (SR) is an organelle in the sarcoplasm.
The SR is a store for calcium (Ca2+) ions. This is important in muscle contraction.
Muscle fibres also have many mitochondria and nuclei.
The mitochondria provide lots of ATP to power muscle contraction.
Myofibrils are cylindrical organelles that run along the length of muscle fibres.
Myofibrils are the site of muscle contraction.
what is nervous system made of
peripheral nervous system and central nervous system
