week 5 Flashcards
what main NS is the automatic nervous system apart of
PNS
what are the 2 main sysment in the ANS and what do they control
sympathetic NS which is activated in fight or flight
parasympathetic is activated during rest and digest
Explain the roles of higher nervous centres in the regulation of parasympathetic and sympathetic nervous functions
Hypothalamus is a higher centre in brain which will control ANS and be responsible for basic survival strategies (reproduction, growth, metabolism, hunger, thirst, temperature control, sleep-wakefulness)
Explain the structure and function of the sympathetic and parasympathetic nervous systems
structure: thoracolumbar region of spinal cord with short preganglionic and long postganglionic fibres located close to spinal cord
Mobilises the body during activity; is the “fight-or-flight” system.
Promotes adjustments during exercise, or when threatened.
Increased heart rate!
Blood flow is shunted to muscles and heart
Bronchioles dilate
Liver releases glucose (from GLYCOGEN)
Explain the structure and function of the sympathetic
structure: brain and sacral spine with long preganglionic and short postgangiloic located in visceral effector organs
Promotes maintenance activities and conserves body energy: ‘rest and digest’.
Its activity is illustrated in a person who relaxes, reading, after a meal:
↓ blood pressure, heart rate deceleration, ↓ respiration rate
Gastrointestinal tract activity is high
Demonstrate the roles of hormones, neurotransmitters, and their receptors in conveying sympathetic
Noradrenaline
eg
alpha - (type 1: excitatory /type 2 : inhibitory) sphincters and glands of GIT
beta1 - excitation, cardiac muscle, liver
beta2 - inhibitory, relaxation bronchial smooth muscle, blood vessels to cardiac.
Two special cases for sympathetic nervous system:
Innervation of adrenal gland (only one ganglionic neuron)
Innervation of sweat glands (with release of Ach by post ganglionic neuron acting on muscarinic receptors in sweat glands).
hyperreflexia
increased or overactive reflexes
areflexia
absence of reflexes
hyporeflexia
decreased reflexes
what is an innate reflex
basic neural reflexes, formed before birth and can disappeared with age (such as Grasp reflex (grabbing object if object touch palm) or Moro reflex (protective motor response against abrupt disruption of body balance), or still be maintained if still useful (such as blinking reflex),
what are acquired reflexes
rapid, automatic, learned motor patterns
what are VISCERAL reflexes
autonomic such as control of heart rate, OR SOMATIC reflexes: stretch such as patellar reflex
what are SPINAL and CRAINIAL reflexes
involving spinal cord as integration center (in some cases information can be relayed to brain), OR CRANIAL reflexes involving brain ONLY as integration center (such as pupillary reflex)
what are mono reflexes
MONO: one synapse involved such as in patellar reflex, OR POLY-SYNAPTIC: such as the crossed extensor reflex or withdrawal reflex.
Ageing effects on nervous system
1) Rapid decline in brain weight: by age 80 years brain weight has declined by 15%
2) Reduced bulk of gyri and widening of sulci: superior parietal gyri, middle frontal gyri
3) Reduction of synaptic connections and neurons
4) Reduced biochemical activity:
* reduced ion channels
* reduced number of receptors
reduced levels of neurotransmitters
