| 1. activated by centers in brain, spinal cord and hypothalamus
2. controls visceral functions (ex. arterial pressure, GI, sweating, peeing)
3. happens QUICK | characteristics of ANS (3) |
| 1. parasympathetic
2. sympathetic | what are the two divisions of the ANS? |
| fight; flight | the way to remember sympathetic NS is "______ or ______" |
| rest; digest | the way to remember parasympathetic NS is "_____ and ______" |
| 1. cardiac muscle
2. smooth muscle
3. glands | what are the effector organs of the ANS? (3) |
| 1. preganglionic neurons-> from CNS to ganglions
2. ganglion-> small mass of nerve tissue containing cell bodies
3. postganglionic neurons-> fibers from ganglion to effector organ | what is the organization of the neurons in ANS? |
| T1-L2
-pass from here into sympathetic chain then into tissue/organs | where do sympathetic neurons originate from? |
| 1. preganglionic neurons= short; from spinal cord to ganglion
2. ganglion= sympathetic chain, periphery, adrenal medulla
3. postganglionic neurons= long; sympathetic trunk to effector organs | characteristics of preganglionic neurons, ganglion, and postganglionic neurons in sympathetic NS |
| ganglion located outside of sympathetic trunk that sympathetic preganglionic nerves can synapse with | what are collateral ganglion? |
| 1. CN 3, 7, 9, 10
2. sacral s.c 2 & 3 | where do parasympathetic nerves originate from? |
| vagus nerve (CN 10)
-pass to thoracic & abdominal region of body | where do 75% of all parasympathetic nerves arise from? |
| 1. preganglionic neurons-> long; travel all the way to organ to be controlled
2. ganglion-> lie near (terminal ganglia) or w/i (intramural) organ
3. postganglionic neuron-> very short; located w/i organ itself | characteristics of preganglionic neurons, ganglion, and postsynaptic neurons in parasympathetic NS. |
| terminal ganglia | what is the name of a ganglion located near the organ in the parasympathetic NS? |
| intramural ganglia | what is the name of a ganglion located within the organ itself in the parasympathetic nervous system? |
| 1. cholinergic
2. adrenergic | name the two types of nerve fibers (based off what NTs they transmit) |
| acetylcholine (Ach) | cholinergic nerve fibers secrete: |
| norepinephrine (NE) | adrenergic nerve fibers secrete: |
| TRUE | T/F: ALL preganglionic n fibers are cholinergic. |
| FALSE | T/F: almost all postganglionic n fibers in the parasympathetic NS are adrenergic. |
| TRUE | T/F: most postganglionic n fibers in sympathetic NS are adrenergic. |
| 1. nicotinic
2. muscarinic | two types of cholinergic receptors |
| -cholinergic receptors (bind Ach)
-b/w the preganglionic n fibers and postganglionic n fibers of para AND symp
**remember that cholinergic responsible for ALL preganglionic n fibers | nicotinic receptors |
| -cholinergic receptors (bind Ach)
-found b/w postganglionic n fibers and effectors organs of either para OR symp (rare)
**remember that adrenergic n fibers mostly responsible for postgang in symp (secrete NE)
**only exception for muscarinic in symp is sweat glands | muscarinic receptors |
| 1. alpha
2. beta | two types of adrenergic receptors |
| 1. NE-> primarily excites alpha
2. Epinephrine-> excites alpha and beta equally | what are alpha adrenergic receptors excited by? |
| 1. NE-> beta to lesser extent than what they excite alpha
2. Epinephrine-> excite alpha and beta equally | what are beta adrenergic receptors excited by? |
| adrenal medulla | epinephrine is produced where? |
| 1. NE
2. E | what NTs are used in sympathetic nervous system? |
| 1. Acetylcholine (Ach) | what NTs are used in parasympathetic nervous system? |
| 1. release NE and E
2. fight or flight
3. increase HR, blood glucose, and diameter of bronchioles | what is role of sympathetic nervous system? |
| 1. release Ach
2. relaxing effect; "rest and digest"
3. decrease HR, visceral blood vessels
4. increase digestive activity | what is role of parasympathetic nervous system? |
| 1. norepinephrine
2. epinephrine | what two substances are NTs than can act as hormones? |
| 1. superior to each kidney
2. consists of: outer adrenal cortex & inner adrenal medulla | where is the adrenal gland located? |
| 1. MAJOR organ of sympathetic NS
2. largest sympathetic ganglia
3. stimulated by preganglionic fibers to secrete NE and E
4. contains spherical chromaffin cells (modified postgang symp neurons) | characteristics of adrenal medulla |
| modified postganglionic sympathetic neurons that help secrete NE and E | what are spherical chromaffin cells? |
| 1. preganglionic neuron exits CNS
2. long pregang n runs down & connects with spherical chromaffin cells (post gang)-> in adrenal medulla
3. spherical chromaffin cells signal to secrete NE & E into blood | how does activation of adrenal medulla work in sympathetic NS? |
| 1. bind to adrenergic receptor (alpha or beta)
2. induces same effects as direct symp NS stimulation
3. short term stress response | what happens to NE & E after being released into blood by sympathetic NS? |
| 1. supports one another
2. can be substituted for the other
3. if one not working, other can compensate | what is the value of having two ways to stimulate the sympathetic nervous system? |
| 1. carotid arteries (2)
2. vertebral arteries (2) | what four arteries directly supply blood to the brain? |
| circle of willis
-which gives rise to pial arteries -> intercerebral arteriosis-> capillaries | the vertebral arteries merge to form what? |
| 1. 2
2. 15 | the brain makes up __% of body weight and __% of cardiac output |
| TRUE | T/F: CBF is highly related to tissue metabolism. |
| 1. metabolic factors
2. autoregulation
3. autonomic control | list the three ways CBF is regulated |
| 1. CO2 & H+ concentration
2. O2 deficiency
3. substances released by astrocytes | list the three ways metabolic factors help regulate the CBF |
| 1. increased CO2 in arterial increases CBF by generating H+
2. increased H+
--depresses neuronal activity
--vasodilation-> increased blood flow
--carries H+ CO2 away
--reduce H+ back to normal
--maintain constant level of neuronal activity | metabolic factors: CO2 & H+ gradient |
| 1. normal O2 conc= 35-40 mmHg
2. cerebral tissue < 30mmHg
--vasodilation to increase CBF & return O2 conc to normal
**important protective response against decreased cerebral neuronal activty | metabolic factors: O2 deficiency |
| increased vasodilation in response to O2 deficiency | what is a protective response against decreased cerebral neuronal activity? |
| 1. electric stimulation of excitatory glutaminergic n.
2. increased Ca2+ in astrocyte endfoot
3. vasodilation of nearby arterioles by releasing vasoactive metabolites
--nitric oxide
--K+
--adenosine
--metabolite of arachidonic acid | metabolic factors: substances released by astrocytes |
| star shaped non-neuronal cells that support and protect neurons & provide nutrition | what are astrocytes? |
| 1. arterial pressure fluctuates during normal daily activities
--increase during excitement, decrease during sleep
2. normally autoregulation fluctuates b/w 50-150mmHg
--<50mmHg-> CBF drops severely can lead to coma
-->150mmHg-> headaches, edema, BBB disruption
** MOST IMPORTANT control of CBF | autoregulation of CBF |
| ability of tissue to regulate blood flow according to arterial pressure | what is autoregulation? |
| autoregulation | what is the most important regulator of CBF? |
| 1. strong symp innervation from sup cerv gangl to large cereral a & arteries that penetrate the brain
2. weak symp vascular tone
3. autoregulation not affected by n supply | sympathetic autonomic control of CBF |
| 1. innervation of facial nerve (CN 7)
2. weak dilatory effect on vessels | parasympathic autonomic control of CBF |
| MINOR | autonomic control has major/minor control of regulating CBF |
| constricts large/intermediate sized arteries in brain to prevent increased pressure reaching small brain blood vessels and causing vascular hemmorhages | clinical importance of sympathetic NS in preventing stroke |
| clear, water-like liquid w/i & around brain and spinal cord | what is cerebrospinal fluid? |
| 1. chambers in brain (ventricles)
2. cisterns around the outside of the brain
3. subarachnoid spaces b/w brain & skull
4. spinal cord (central canal) | areas CSF is formed in (4): |
| 1. cushion/protect brain & s.c
2. reservoir & regulate content of cranium
3. medium for nutritional exchange in CNS
4. transport hormones & hormone releasing factors
5. removes metabolic waste products through absorption | functions of CSF (5) |
| 1. blood CSF barrier
2. blood brain barrier | two types of brain barriers |
| 1. increased permeability to H2O, CO2, O2, and most lipid soluble molc (ex. alcohol & anesthetics)
2. slightly permeable to Na+, Cl-, K+
3. glucose transported across brain capillaries by GLUT 1
4.impermeable to placenta proteins & non-lipid soluble large organic molc | permeability characteristics of barriers (4) |
| 1. homeostasis: maintains optimal environment of neurons
2. selective barrier
3. prevent escape of NTs
4. protect brain from toxins & other harmful substances | functions of barriers (4) |
| 1. hypertension
2. hyperosmolarity
3. microwaves
4. radiation
5. infection
6. injury to brain: trauma, ischemia, inflammation | causes of damage to BBB (6) |
| 1. cell damage
2. increased permeability
3. immune cell adhesion & transmigration
4. increased inflammatory responses | consequences of damage to BBB (4) |
| 1. tight junctions
2. adherons junctions | two types of junctions b/w endothelial cells in BBB |
| 1. three things seal the space b/w endothelial cells
--JAMS
--Claudin (3/5)
--Occludin
2. zone occluding molecules (ZO)= connect TJs to actin/myosin cytoskeleton | tight junctions |
| 1. VE-cadherin= structural integrity & TJ formation
2. catenin= scaffolding protein linked to cytoskeleton | adherons junctions |
