Honors Anatomy Physiology THE AUTONOMIC NERVOUS SYSTEM ANS

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Honors Anatomy & Physiology THE AUTONOMIC NERVOUS SYSTEM

Honors Anatomy & Physiology THE AUTONOMIC NERVOUS SYSTEM

ANS � in PNS � operates via reflex arcs � includes: � autonomic sensory

ANS � in PNS � operates via reflex arcs � includes: � autonomic sensory neurons � integrating centers in CNS � autonomic motor neurons

AUTONOMIC REFLEX ARC

AUTONOMIC REFLEX ARC

AUTONOMIC MOTOR NEURONS � when somatic motor neurons sends impulse to a muscle the

AUTONOMIC MOTOR NEURONS � when somatic motor neurons sends impulse to a muscle the effect always excitatory…if they stop sending impulses that muscle atrophies � autonomic motor neurons regulate visceral activities by either increasing (exciting) or decreasing (inhibiting) ongoing activities in their effector tissues (cardiac or smooth muscle, glands)

COMPARISONS OF ANS & SOMATIC NS

COMPARISONS OF ANS & SOMATIC NS

AUTONOMIC SENSORY NEURONS � source of most input to ANS via sensory receptors called

AUTONOMIC SENSORY NEURONS � source of most input to ANS via sensory receptors called interoceptors � not consciously perceived most of time � located in: � blood vessels � visceral organs � muscles � in nervous system

AUTONOMIC RESPONSES � most cannot be altered to any great degree making some responses

AUTONOMIC RESPONSES � most cannot be altered to any great degree making some responses ideally suited for lie detector tests

AUTONOMIC MOTOR PATHWAYS � most consist of 3 motor neurons in series � 1

AUTONOMIC MOTOR PATHWAYS � most consist of 3 motor neurons in series � 1 st neuron has cell body in CNS myelinated axon synapses in autonomic ganglion with 2 nd motor neuron cell body: its unmyelinated axon effector � except

AUTONOMIC MOTOR PATHWAY

AUTONOMIC MOTOR PATHWAY

SYMPATHETIC DIVISION � � preganglionic axons from thoracolumbar nerves ganglia far from visceral effector

SYMPATHETIC DIVISION � � preganglionic axons from thoracolumbar nerves ganglia far from visceral effector in: � � sympathetic chain or collateral ganglia neurotransmitter used: � � ACh in ganglia NE in effector organ PARASYMPATHETIC DIVISION � � � preganglionic axons from craniosacral nerves ganglia near or w/in visceral effector organs neurotransmitter used: � � ACh in ganglia ACh in effector organ 2 BRANCHES OF MOTOR PART OF ANS

MOTOR PART OF ANS � most organs have dual innervation � nerve impulses from

MOTOR PART OF ANS � most organs have dual innervation � nerve impulses from 1 will increase activity (excitation) & impulses from other decrease activity (inhibition)

SYMPATHETIC GANGLIA � 2 1. groups: sympathetic trunk ganglia 1. 2. lie in vertical

SYMPATHETIC GANGLIA � 2 1. groups: sympathetic trunk ganglia 1. 2. lie in vertical row, either side of vertebrae prevertebral ganglia 1. lie anterior to vertebral column close to large abdominal arteries

SYMPATHETIC DIVISION OF ANS

SYMPATHETIC DIVISION OF ANS

PARASYMPATHETIC GANGLIA � most close to or w/in effector organ

PARASYMPATHETIC GANGLIA � most close to or w/in effector organ

EFFECTS OF SYMPATHETIC & PARASYMPATHETIC DIVISIONS OF THE ANS

EFFECTS OF SYMPATHETIC & PARASYMPATHETIC DIVISIONS OF THE ANS

HOMEOSTATIC IMBALANCES OF THE ANS � Raynaud’s � due phenomenon: to excessive sympathetic stimulation

HOMEOSTATIC IMBALANCES OF THE ANS � Raynaud’s � due phenomenon: to excessive sympathetic stimulation of smooth muscles in arterioles of digits � digits become ischemic (lack of blood) after exposure to cold or with emotional stress

MEDICAL TERMINOLOGY � autonomic nerve neuropathy: often caused by long-standing diabetes, neuropathy affects 1

MEDICAL TERMINOLOGY � autonomic nerve neuropathy: often caused by long-standing diabetes, neuropathy affects 1 or more autonomic nerves, can interfere with reflexes � hyperhydrosis: profuse sweating due to intense stimulation of sweat glands � vagotomy: cutting vagus nerve; often done to decrease production of HCl in patients with severe ulcers