BIOL 460 1nd Edition Lecture 4 Outline of Last Lecture I. Inhibitory Amino Acid NTMsA. GABAII. Polypeptide NeurotransmittersIII. Lipid NTMsIV. Gaseous NTM (end of Chapter 7)V. Autonomic Nervous System (beginning of Chapter 9)Outline of Current Lecture I. Sympathetic division a. Sympathoadrenal systemII. Parasympathetic division III. Autonomic Function IV. NTMs in ANSa. Achi. Cholinergic neurons ii. Cholinergic receptors Current LectureSympathetic Division (thoracolumbar division)1. Cell bodies of preganglionic neurons are segments of the spinal cord T1-L2a. Vertebrae b. Cervical- 7 segments, 7 neuronsc. Thoracic- ribsd. Lumbare. Sacralf. Coccygeal 2. Figure 9.3 shows pathways of axons a. Leave spinal cord → ventral root → spinal nerveb. Branch called white ramus communicantes (axons of pre-ganglionic neurons)c. Sympathetic chain composed of chain ganglia (paravertebral ganglia)i. Cell bodies of sympathetic post-ganglionic neurons ii. Post-ganglionic axons can do three things with chain These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.1. Axons beneath diaphragm will pass directly through sympathetic chain and for splanchnic nerve that enters abdominal cavity- collateral ganglia a. Also known as pre-vertebral gangliab. 3 named for arteries branching formationi. Celiac ii. Superior mesenteric iii. Inferior mesenteric c. Contain cell bodies of sympathetic post-ganglionic neuron d. Innervate digestive, reproductive, and urinary systems 2. Sympathetic pre-ganglionic axons enter chain ganglion and immediately synapse with a sympathetic-post-ganglionic neuron a. Carried through grey ramus communicantes, unmyelinated axonsb. Supplies visceral effectors in somatic part of body (skin glands, smooth muscle in blood vessels supplying the skeletal muscles, erecter pill muscles)c. Can go up or down chain ganglia 3. Sympathoadrenal systema. Major NTM→ norepinephrine b. Released by sympathetic post-ganglionic neurons c. Related to adrenal glandi. Sits on top of kidneys, endocrine glandii. Excretes catecholamines into blood stream iii. Bond to same receptors as norepinephrine- adrenergic receptors iv. Adrenal medulla releases 15% norepinephrine and 85% epinephrine, part of ectotdermv. Adrenal cortex releases corticosterioids, part of mesoderm vi. Medulla formed from ectoderm (neural crest)1. Neural crest forms all ganglia in body 2. Adrenal medulla is a modified sympathetic collateral ganglion Parasympathetic Division (craniosacral division)1. Cell bodies of parasympathetic pre-ganglionic neurons are in nuclei within the brain and sacral segments 2-4 (leave via pelvic nerves)2. Axons of pre-ganglionic neurons go quite a long distance 3. Synapse with parasympathetic post-ganglionic neurons where cell bodies are in terminal ganglia 4. Terminal ganglia are close to or within tissue of target organ5. Most parasympathetic innervation is through the vagus nerve (X cranial nerve)6. Enormous cranial nerve, from medulla through chest cavity into abdominal cavity7. Reach terminal gangliona. Cell bodies of parasympathetic post-ganglionic neurons b. Very near or within target organs 8. No parasympathetic axon in spinal nerves (unlike sympathetic)a. Visceral effectors in somatic part of body receive no parapsympathetic innervation Autonomic Function1. Sympathetic- fight or flight 2. Parasympathetic- repass and repose 3. Stomach receives both types of divisions (heart as well)4. Adrenal medulla- sympathetic only5. Visceral effector in somatic part of body- sympathetic onlyNeurotransmitters in ANS1. Acetylcholine (Ach)a. Cholinergic neurons i. All autonomic pre-ganglionic neuronsii. Most parasympathetic post-ganglionic neurons iii. Some sympathetic post-ganglionic neurons1. Glands in skin, erector pill muscle, some supplying vascular tissue in skeletal muscleb. Cholinergic receptorsi. nicotinic→ EPSPs, found on ANS ganglia and adrenal medulla ii. muscarinic 1. EPSP or IPSP 2. IPSP in heart 3. Found on visceral effectors (cardiac muscle, smooth muscle, glands)4. Receptors of vascular smooth muscle are muscarinic 5. Figure 9.9a. Axons on post-ganglionic neurons have enlargements called variscositiesb. In both divisions of ANS c. NTM released at terminal bouton and at variscosities d. Synapsing with smooth muscle cells down its length e. Parasympathetic releases Ach, Sympathetic releases norepinephrine f. Synapses here are called synapses en passant 6. Nicotinic receptors have curare as an antagonist (tree frog poison)- causes paralysis7. Muscarinic receptors are blocked by atropine