PNS Autonomic nervous system Autonomic NS regulates smooth

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PNS: Autonomic nervous system Autonomic NS regulates smooth muscle, cardiac muscle, gland tissue and

PNS: Autonomic nervous system Autonomic NS regulates smooth muscle, cardiac muscle, gland tissue and adipocytes • Anatomy of efferent pathways – Sympathetic vs parasympathetic vs somatic motor – Location of neurons and synapses – Neurotransmitters • Specific autonomic neuron functions • Neurotransmitter receptor mechanisms

* Autonomic efferent neurons: preganglionic and postganglionic

* Autonomic efferent neurons: preganglionic and postganglionic

Neural Systems

Neural Systems

Parasympathetic Division • • “Rest and digest”, relaxed state Does not typically activate as

Parasympathetic Division • • “Rest and digest”, relaxed state Does not typically activate as a whole Decrease HR, increase digestive fxn Preganglionic neurons originate in midbrain, medulla, pons and 2 -4 sacral • Preganglionic fibers long, post short

Sympathetic Division • Fight or flight (prepares for intense activity) • Heart rate increases,

Sympathetic Division • Fight or flight (prepares for intense activity) • Heart rate increases, bronchioles dilate, plasma [glucose] increases • Preganglionic neurons originate from spinal cord from T 1 to L 2 spinal nerves • Preganglionic short, post-long • Can have mass action: distributed to heart, blood vessels, skin, adrenal glands

http: //medlib. med. utah. edu/kw/hyperbrain/anim/reflex. html

http: //medlib. med. utah. edu/kw/hyperbrain/anim/reflex. html

Neurotransmitters and Receptors • ACh receptor = cholinergic receptors – nicotinic – muscarinic •

Neurotransmitters and Receptors • ACh receptor = cholinergic receptors – nicotinic – muscarinic • NE and E receptor = adrenergic – 1 and 2 (alpha) – 1 and 2 (beta)

Human Physiology, 6 th ed. , Fox, SI; WC Brown, Fig. 9. 9

Human Physiology, 6 th ed. , Fox, SI; WC Brown, Fig. 9. 9

Parasympathetic • preganglionic ACh : nicotinic receptor … is a Na+ / K+channel •

Parasympathetic • preganglionic ACh : nicotinic receptor … is a Na+ / K+channel • postganglionic ACh: muscarinic rec. G-protein coupled receptor links to 2 nd messenger; several different kinds

Sympathetic • preganglionic ACh : nicotinic receptor …is a Na+ / K+channel • postganglionic

Sympathetic • preganglionic ACh : nicotinic receptor …is a Na+ / K+channel • postganglionic NE: adrenergic receptor, alpha or beta, G-protein coupled receptor links to 2 nd messenger (see Table 11. 1)

Adrenergic receptors Rec. Intrac. effect Functional roles, locations 1 IP 3, DAG contractile for

Adrenergic receptors Rec. Intrac. effect Functional roles, locations 1 IP 3, DAG contractile for smooth m. , blood vessels 2 c. AMP inhibitory, GI tract, pancreas 1 c. AMP cardiac muscle, kidney 2 c. AMP relaxes smooth m. , GI tract, blood vessels, bronchioles

Autonomic Motor NS • Central control by limbic system, hypothalamus, brainstem, spinal cord. •

Autonomic Motor NS • Central control by limbic system, hypothalamus, brainstem, spinal cord. • Adrenergic receptors. • Example pathways with autonomic motor efferents.

Influence of Brain on Autonomic Functions Thoughts & emotions influence ANS by hypothalamus. ANS

Influence of Brain on Autonomic Functions Thoughts & emotions influence ANS by hypothalamus. ANS integrating center that interacts with cerebrum, limbic system, brainstem, and spinal cord. ANS reflex centers for controlling pupil size, accomodation, tear production, salivation, coughing, digestive activities, heart, blood vessel diameter and respiration. ANS reflex control of defecation, urination, genital erection and ejaculation.

Spinal cord

Spinal cord