Nervous System Flashcards
What is the nervous system?
A network of specialised cells that communicate information about an individuals surroundings and itself. It processes this information and causes reactions in other parts of the body.
Why does the nervous system do?
Analyses sensory information from the body and the external environment. It stores some aspects and makes decisions regarding appropriate responses and behaviours
How does the nervous system make motor responses ?
By initiating muscular contractions or glandular secretions
What is the nervous system composed of
Central nervous system
Peripheral nervous system
What is the central nervous system composed of ?
Brain and spinal cord
What is the peripheral nervous system composed of?
composed of sensory nerves and motor nerves connecting the CNS to the rest of the body.
What do peripheral nerves contain?
a sensory pathway consisting of sensory nerves and/or a motor pathway consisting of motor nerve cells
What do sensory pathways do?
keep the brain in touch with what is going on in the body’s external and internal environments.
What 2 systems make up the peripheral nervous system?
Somatic nervous system (mostly voluntary)
Autonomic nervous system (involuntary)
What is the autonomic nervous system composed of?
sympathetic system
parasympathetic system
What do sensory and motor neurons of the somatic nervous system control?
the voluntary movement of skeletal muscles. The somatic nervous system is also responsible for bringing about certain involuntary reflex actions (e.g. limb withdrawal)
What does the autonomic nervous system control?
involuntary responses to stimuli by the body, so there is no conscious control, but under exceptional circumstances some people can suppress certain autonomic responses intentionally.
Name 5 aspects of the body that are regulated by autonomic nerves?
heart blood vessels bronchial tubes alimentary canal sweat glands
How does the ANS try to maintain a stable internal environment ?
by playing the role of HOMEOSTATSIS.
What are the branches of the ANS said to be?
antagonistic and have opposite effects on the SAME organs.
How does the ANS have finely tuned control over effectors?
they are stimulated by both sympathetic and parasympathetic nerves
What does the sympathetic system do?
prepares the body for action (fight or flight) and the expenditure of energy
What does the parasympathetic system do?
calms the body down (rest and digest) and try to conserve energy or resources
What effect does the sympathetic system have on the heart?
Rate and force of contraction of cardiac muscle increases. Result: increased cardiac output of blood.
What effect does the parasympathetic system have on the heart?
Rate and force of contraction of cardiac muscle decreases. Result: decreased cardiac output of blood.
What effect does the sympathetic system have on the bronchioles?
Smooth muscle in wall of bronchiole becomes relaxed. Result: Bore of tube becomes dilated allowing increased volume of air to enter lung.
What effect does the parasympathetic system have on the bronchioles?
Smooth muscle in wall of bronchiole becomes contracted. Result: Bore of tube becomes constricted allowing decreased volume of air to enter lung.
What effect does the sympathetic system have on the digestive tract?
Rate of contraction of smooth muscle in wall of digestive tract decreases. Result: decreased rate of peristalsis
What effect does the parasympathetic system have on the digestive tract?
Rate of contraction of smooth muscle in wall of digestive tract increases. Result: increased rate of peristalsis
What effect does the sympathetic system have on the intestines?
Activity of secretory glands in intestines wall is inhibited. result: Decreased production of intestinal secretions.
What effect does the parasympathetic system have on the intestines?
Activity of secretory glands in intestines wall is stimulated. result: increased production of intestinal secretions.
What effect does the sympathetic system have on the adrenal glands?
Adrenal gland is stimulated. Result: Increased rate of secretion of hormone epinephrine (adrenaline)
What effect does the parasympathetic system have on the adrenal glands?
No parasympathetic nerve connection to adrenal gland. Result : No effect.
What is the brain?
an organ with millions of neurons that controls the body.
The brain is a complex organ, what are the 3 interconnected, concentric layers?
central core
limbic system
cerebral cortex (outer layer of cerebrum)
What is the central core composed of?
medulla and cerebellum
What does the medulla do?
controls breathing, heart rate, sleep and arousal.
What does the cerebellum do?
controls balances, muscular coordination, posture & movement?
What is the limbic system described as?
a composite area of the brain
What does the limbic system have?
structures that project deep into the cerebral cortex
What are the structures that project deep into the cerebral cortex involved in?
processing information needed to form long-term memories
regulating emotional states (e.g. anxiety, fear and aggression)
influencing biological motivation (e.g hunger, thirst and sex thrive)
What is another part of the limbic system?
the hypothalamus
What is the hypothalamus connected to and what does this act as?
pituitary gland and acts as a link between the nervous system and the hormonal system
What does the hypothalamus contain?
secretory cells that produce releaser hormones
What does the hypothalamus do?
regulates autonomic activities. contains osmoreceptors to detect changes in water concentration and thermoreceptors to detect changes in temperature
What is the cerebral cortex?
outer layer of the cerebrum which is the centre of conscious thought; it recalls memories and alters behaviour in light of experience. The largest and most complex part of the brain
The brain is split into 2 halves, what are these called?
cerebral hemispheres
How are the 2 sides of the brain joined together?
by the corpus callosum
What is the corpus callosum?
a large bundle of nerve fibres
What does the corpus callosum allow?
information to be transferred from one side to the other.
What does each side of the brain control?
the other side of the body.
In the cerebrum what are the 3 main types of functional area, which are all discrete (they have there own function)?
sensory
Association
Motor
What is the role of sensory areas?
Sensory areas receive information as sensory impulses from the body’s receptors (e.g. touch receptors in the skin and thermoreceptors in the hypothalamus)
What is the role of association areas?
association areas analyse and interpret sensory impulses, ‘make sense’ of them and ‘take decisions’ if necessary.
What is the role of motor areas?
motor areas receive information from the association areas and ‘carry out orders’ by sending motor impulses to the appropriate effectors (e.g. muscles). By this means, coordination of voluntary movement is effected.
What does the localisation of brain functions include?
sensory areas
motor areas
association areas concerning language, personality, imagination and intelligence.
