Chapter 15: Chemical Control of the Brain and Behavior Flashcards
1
Q
What does proper function require?
A
Restricted synaptic
communication
2
Q
- Sits along wall of 3rd ventricle
- Connected by a stalk to the
pituitary - Two lobes: anterior and
posterior - Integrates somatic and visceral responses in accordance with the needs of the brain
- 3 F’s
A
Hypothalamus
3
Q
- Regulates body temperature and blood composition within a narrow physiological range in response to external environment
- responds to a sensory stimulus with humoral,
visceromotor, and somatic motor responses
A
Homeostasis
4
Q
In cold weather, how does homeostasis work?
A
- Adjusts balance of sympathetic and
parasympathetic outputs of the ANS - Ex: Constrict blood vessels to minimize peripheral blood flow
- Incites appropriate somatic motor
behavioral response - Ex: Shivering
- Stimulates or inhibits release of pituitary
hormones (humoral) - Conserve water within the body – release vasopressin
5
Q
3 zones of the hpothalamus
A
lateral, medial, periventricular
6
Q
____________ zone lies next to 3rd ventricle
A
Periventricular
7
Q
Lateral and medial zones have connections with what?
A
brain stem and cortex
8
Q
What contains the suprachiasmatic nucleus (SCN)?
A
Periventricular zone
9
Q
Regulates circadian rhythms (biological clock)
A
Suprachiasmatic nucleus
10
Q
Send axons to the stalk of the pituitary
A
Neurosecretory cells
11
Q
Posterior pituitary is _______ ________.
A
brain tissue
12
Q
- Largest secretory cells
- Extend axons down the stalk into posterior
pituitary - release two neurohormones into bloodstream.
A
Magnocellular neurosecretory cells
13
Q
What two neurohormones that are released into bloodstream by Magnocellular neurosecretory cells?
A
- Oxytocin
- Vasopressin (ADH)
14
Q
- “love hormone”
- Promotes social bonding, Lactation
A
Oxytocin
15
Q
- Regulates blood volume and salt concentration
- ADH-containing neurons receive info about
these changes and release vasopressin - Acts directly on the kidney
- leads to water retention and reduced urine production
A
Vasopressin (ADH)
16
Q
“Master gland” of the endocrine system
A
Anterior lobe
17
Q
What controls the anterior pituitary gland?
A
parvocellular neurosecretory cells
18
Q
- Do not extend axons all the way into the
anterior lobe—project to the median
eminence - Communicate via bloodstream
- Secrete hypophysiotropic hormones
- via a network of blood vessels: hypothalamo-pituitary portal
circulation - hypophysiotropic hormones bind to receptors on the surface of pituitary cells
-> Activation causes pituitary cells to secrete or stop secreting hormones
A
parvocellular neurosecretory cells
19
Q
What do parvocellular neurosecretory cells do in response to stress? (first step)
A
secrete corticotropin-releasing hormone (CRH—aka: CRF) into portal circulation
20
Q
second step in stress response
A
CRH travels to anterior pituitary and
stimulates the release of
adrenocorticotropic hormone (ACTH)
21
Q
third step in stress response
A
ACTH enters general circulation»> travels to the adrenal cortex (in kidney)
* stimulates glucocorticoid (cortisol in primates: aka “stress hormone”)
release from adrenal cortex
* Cortisol inhibits CRH release (negative feedback via hippocampus)
22
Q
- Part of the PNS
- Carried out without conscious control
- commands every other innervated tissue and organ in the body
-> Widespread actions instead of pinpoint accuracy - Sympathetic division: “fight or flight”
- Parasympathetic division: “rest and digest”
A
Autonomic Nervous System
23
Q
Mobilizes the body for a short term emergency at the expense of processes that keep it healthy long-term
A
Sympathetic Division
24
Q
Works calmly for long-term good
A
Parasympathetic Division
25
What type of neurons does the sympathetic and parasympathetic division have?
Preganglionic neurons
26
* Cells bodies in thoracic and lumbar cord
* Send axons through ventral roots to synapse on sympathetic chain ganglia or within collateral ganglia in abdominal cavity
Preganglionic neurons in SYMPATHETIC division
27
* Cells bodies sit within brain stem and sacral spinal cord
* Axons travel within several cranial nerves and sacral nerves
* Axons travel much farther than sympathetic axons b/c
parasympathetic ganglia are
located next to or on target organs
Preganglionic neurons in PARASYMPATHETIC division
28
* Driven by preganglionic neurons (UMNs): cell bodies are in the CNS
* Di-synaptic control of targets
Autonomic ganglia
29
What neurotransmitter is at the autonomic ganglia?
ACh (acetylcholine)
30
Postganglionic synapse for sympathetic
- Far-reaching effects—even into
blood
norepinephrine
31
Postganglionic synapse for parasympathetic
- Local effect—near target
organs
- Acts entirely through mAChRs
ACh (acetylcholine)
32
mimic or promote muscarinic actions of ACh or
inhibit actions of NE
Parasympathomimetic
33
mimic or promote NE actions or inhibit muscarinic actions of ACh
Sympathomimetic
34
- main regulator of autonomic preganglionic neurons
- Integrates the info it receives about the body’s status, anticipates its needs, and provides neural and hormonal output
- Periventricular zone connections to brain stem and spinal cord nuclei that contain preganglionic neurons
Hypothalamus
35
Integrates sensory information from internal organs and coordinates output to autonomic brain stem nuclei
Nucleus of solitary tract (medulla)
36
solely functions to innervate and
control skeletal muscles
Somatic Motor System
37
Cell bodies of all somatic LMNs are in CNS
* Monosynaptic control of targets
Somatic Motor System
38
ACh at NMJ
Somatic Motor System
39
is a synaptic connection between the terminal end of a motor nerve and a muscle
neuromuscular junction (NMJ)
40
Locus of central control: motor cortex and brainstem
Somatic Motor System
41
commands every other innervated tissue
and organ in the body
* Widespread actions
* Cell bodies of LMNs in ANS are outside
CNS>>> autonomic ganglia
* Disynaptic control of targets
ANS
42
ACh is NT in preganglionic neurons in ANS
*NE: postganglionic fibers in sympathetic
*ACh: postganglionic fibers in parasympathetic
ANS
43
Major locus of central control: hypothalamus
ANS
44
* “Brain in the gut”
* lining of esophagus, stomach, intestines,
pancreas, and gallbladder
* control physiological processes involved
in transport and digestion of food
* sympathetic and parasympathetic
innervation
Enteric Division of ANS
45
What are the 2 networks of the Enteric Division of ANS?
1. myenteric (Auerbach's) plexus
2. submucous (Meissner's) plexus
46
concerned with the motor aspects of gut function (e.g., peristalsis).
myenteric (Auerbach's) plexus
47
concerned with the secretory aspects of gut function
submucous (Meissner's) plexus
48
Axons innervate cerebral cortex, thalamus, hypothalamus, olfactory bulb, cerebellum, midbrain, and spinal cord.
Norepinephrine system in locus coeruleus
49
regulation of attention, arousal, sleep–wake cycles, learning and memory, anxiety and pain, mood, brain metabolism
Norepinephrine system in locus coeruleus
50
Activation: new, unexpected, nonpainful sensory stimuli
* Least active during rest
Norepinephrine system in locus coeruleus
51
innervate many of the same areas as noradrenergic (norepinephrine) system
Serotonin (5HT) system in the Raphe Nuclei
52
together with noradrenergic system, comprise the ascending reticular activating system
* Particularly involved in sleep–wake cycles, mood
Serotonin (5HT) system in the Raphe Nuclei
53
Activation: Most active during wakefulness, when aroused and active
Serotonin (5HT) system in the Raphe Nuclei
54
* Axons project to the striatum
* Facilitates the initiation of
voluntary movements
* degeneration >> PD
Substantia nigra
55
Gives rise to two major pathways:
* Mesolimbic dopamine system: to nucleus accumbens (NAcc)
* Mesocortical dopamine system: to prefrontal cortex
Ventral tegmental area (VTA)
56
DA projection from midbrain to nucleus accumbens (NAcc)
* Involved in the reinforcing and rewarding aspects of drugs
* Humans and animals will self-stimulate
* Heavily investigated in many drugs of abuse
Mesolimbic Dopamine System
57
- Neurons lie scattered at the core
of telencephalon: medial and
ventral to basal ganglia
- Function: mostly unknown,
participates in learning and
memory
* First cells to die during
Alzheimer’s Disease
Basal forebrain complex
58
* Located in pons and midbrain tegmentum
* Provides a link between the brain stem and basal forebrain complex
Pontomesencephalotegmental complex
59
Damage to cholinergic system contributes to cognitive factors in ________________ disease.
Alzheimer's
60
Psychoactive drugs act on the ___________.
CNS
61
Interfere with chemical synaptic transmission
Psychoactive drugs
62
62
LSD, Psilocybin, mescaline>>>5HT2A agonists
Hallucinogens
63
* Cocaine and amphetamine affect dopaminergic and noradrenergic systems
* These drugs produce very high levels of DA and NE in the synaptic cleft
* Sympathomimetic
Psychomotor stimulants
