Chemical control of the brain and behavior

Question 1

Diffuse Modulatory System

Answer 1

• Typically, the core of each system has a small set of neurons (several thousand).
• One of several systems of CNS neurons that project widely and diffusely onto large areas of the brain and use modulatory neurotransmitters, including dopamine, norepinephrine, serotonin, and acetylcholine.
• highly divergent axonal projections and prolong their actions by using metabotropic postsynaptic receptors.

Question 2

Locus Coeruleus

Answer 2

A small nucleus located bilaterally in the pons; using NE as their neurotransmitter, its neurons innervate: all of the cerebral cortex, the thalamus and the hypothalamus, the olfactory bulb, the cerebellum, the midbrain, and the spinal cord

Question 3

The raphe nuclei

Answer 3

• Serotonin-containing neurons are mostly clustered within the nine raphe nuclei.
• clustered along the midline of the brain stem and project extensively to all levels of the CNS.
• fire most rapidly during wakefulness, implicated in the control of mood and certain types of emotional behavior.

Question 4

Substantia

nigra and Ventral tegmental area

Answer 4

-lie close together in the midbrain.
-Dopaminergic cells arises in the substantia nigra in the mid brain
-They project to the striatum (caudate
nucleus and putamen), voluntery movements
-Axons from ventral tegmental area innervate frontal cortex and parts of the limbic system

Question 5

Basal

forebrain complex

Answer 5

• Basal nucleus of Myenert and Medial septai nuclei
• Cholinergic interneurons exist there
• Project widely upon the cerebral cortex, including hippocampus.

Question 6

Pontomesencephalotegmental complex

Answer 6

• Cholinergic interneurons exist there
• Located in the pons and midbrain tegmentum, it is the origin of cholinergic cell bodies in the brainstem. Acts mainly on the dorsal thalamus, but also projects up to the midbrain and parts of forebrain.

Question 7

components of the nervous system that act over great distances and for long periods of time

Answer 7

secretory hypothalamus, autonomic nervous system (ANS), diffuse modulatory systems of the brain

Question 8

Location of secretory hypothalamus

Answer 8

-sits below the thalamus, along the walls of the third ventricle. It is connected by a stalk (runko,tappi) to the pituitary gland (aivolisäke), which dangles below the base of the brain, just above the roof of your mouth

Question 9

Homeostasis of hypothalamus

Answer 9

• regulates body temperature (sweating, shivering, turning blue or red) and blood compositions (koostumus) in response to changing environment.
• tight regulation of blood volume, pressure, salinity (suolaisuus), acidity (happamuus), and blood oxygen and glucose concentrations.

Question 10

Structure and Connections of the Hypothalamus

Answer 10

Each side of the hypothalamus has three functional zones (from out to in): lateral, medial,(regulate certain type of behaviour) and periventricular
-Third ventricle between these sides

Question 11

In periventricular zone exists a complex mix of neurons with different functions. What are these?

Answer 11

• suprachiasmatic nucleus (SCN): These cells receive direct retinal innervation and function to synchronize circadian rhythms with the daily light–dark cycle
• Other cells control the ANS and regulate the outflow of the sympathetic and parasympathetic innervation of the visceral organs
• neurosecretory neurons, extend axons down toward the stalk of the pituitary gland.

Question 12

Hypothalamus control of the posterior pituitary, which cells and the task?

Answer 12

magnocellular neurosecretory cells:

• Largest neurosecretory cells
• Extend axons down the stalk of pituitary and into the posterior lobe.
• Release two neurohormones into bloodstream: oxytocin, vasopressin (ADH)

Question 13

Oxytocin

Answer 13

• Peptide chain, nine amino acids
• final stages of childbirth
• ejection of milk from the mammary glands.
• Love hormone

Question 14

Vasopressin, antidiuretic hormone ADH

Answer 14

• regulates blood volume and salt concentration. (Body deprived of water
• > changes detected by pressure receptors in the cardiovascular system and salt concentration-sensitive cells in the hypothalamus
• > signal to hypothalamus
• > release ADH
• > acts on the kidneys
• > water retention and reduced urine production)

Question 15

Renin enzyme and the followed biochemical reactions in the blood

Answer 15

-Secreted from kidney to blood when lowered blood pressure and volume
- >angiotensinogen by renin ->angiotensin l ->angiotensin ll ->blood vessels, kidney
also
->subfornigal organ->axons to neurosecterory cells and lateral hypothalamus, overwhelming thirst.

Question 16

Anterior Pituitary

Answer 16

• actual gland
• secrete a wide range of hormones that regulate secretions from other glands throughout the body
• The pituitary hormones act on the gonads, the thyroid glands, the adrenal glands, and the mammary glands (kilpirauhanen, lisämunuainen, maitorauhanen)
• release of corticotropin (ACTH)
• FSH, LH, prolactin

Question 17

Hypothalamic Control of the Anterior Pituitary, what cells and how and where?

Answer 17

• parvocellular neurosecretory cells in hypothalamus, in the periventricular area.
• communicate via the bloodstream
• hypophysiotropic hormones into a capillary bed by tiny blood vessels down to anterior lobe of pituitary. This network of blood vessels is called the hypothalamo-pituitary portal circulation.
• specific receptors on the surface of pituitary cells
• > secrete or stop secreting hormones of anterior pituitary into the general circulation.
• control the adrenal cortex determine whether a stimulus is stressful or not
• release a peptide called corticotropin-releasing hormone (CRH) into the blood of the portal circulation.-> stimulates the release of corticotropin, or adrenocorticotropic hormone (ACTH) in anterior pituitary.

Question 18

Adrenal glands (lisämunuaiset)

Answer 18

• above kidneys
• two parts, a shell called the adrenal cortex and a center called the adrenal medulla
• Cortex: cortsiol, mobilize energy reserves and suppress the immune system, stress hormone.
• > In brain, cortisol interacts with specific receptors->inhibition of CRH.

Question 19

adrenal insufficiency(riittämättömyys)

Answer 19

After using a inflammation drug, that increases cortsiol:
-not enough time to ramp up cortisol production in adrenal cortex->causes severe abdominal pain and diarrhea, extremely low blood pressure, and changes in mood and personality. a feature of a rare disorder called Addison’s disease=degeneration(rappeutuminen) of the adrenal gland.

Question 20

flip side of adrenal insufficiency

Answer 20

Cushing’s disease=pituitary gland dysfunction that results in elevated levels of ACTH and, consequently, cortisol. The symptoms include rapid weight gain, immune suppression, sleeplessness, memory impairment, and irritability.

Question 21

FSH, follicle-stimulatin hormone

Answer 21

Target: gonads(sukupuolirauhanen)
Action: ovulation, spermatogenesis

Question 22

LH, Luteinizing hormone

Answer 22

Target: Gonalds
Action: Ovarian (munasarja) and sperm maturation

Question 23

TSH, Thyroid-stimulating hormone (kilpirauhanen)

Answer 23

Target: Thyroid
Action: Thyroxin secretion

Question 24

Adrenocorticotropic, ACTH

Answer 24

Target: Adrenal cortex
Action: Cortsiol secretion

Question 25

Growth hormone, GH

Answer 25

Target: All cells
Action: Stimulation of protein synthesis

Question 26

Prolactin

Answer 26

Target: Mammary glands (maitorauhanen)
Action: Growth and milk secretion

Question 27

Peripheral nervous system

Answer 27

1) sensory NS

2)motor
Somatic NS=voluntery control
Autonomic NS= sympathetic, parasympathetic, enteric

Question 28

Autonomic NS, features and what it innervates, types of tissue(3) and more specific(3) and regulates(7)

Answer 28

• Periventricular zone controls the ANS
• multiple, widespread, and relatively slow
• Takes two motor neurons to get to the effect organ preganglionic, postganglionic
• disynaptic pathway
• innervates three types of tissue: glands, smooth muscle, and cardiac muscle.
• innervates secretory glands, heart and blood vessels to control blood pressure and flow, lungs to meet the oxygen demands
• regultes digestive, matbolic functions of liver, pancreas(haima), functions of kidney, bladder, large intestine(suolisto), and rectum.
• sexual responses
• immune system

Question 29

Sympathetic NS, where and what kind of neurons and tasks(10):

Answer 29

• coming out from Thoraco-Lumbar Segments, area in spinal cord
• Preganglionic nerves are short, postganglionic long
• Interaction of synapses: ACh
• Preganglionic sympathetic neurons: cholinergic neurons
• Postganglionic sympathetic neurons : release NE, adrenergic neurons

-dilates pupil, inhibits salvation, relaxes airways, accelerates heartbeat, stimulates glucose production and release, inhibits digestion, stimulates secterion of NE, epinephrine in adrenal medulla, regulates large intestine, bladder, stimulates orgasm

Question 30

Parasympathetic NS, where and what kind of neurons and tasks(9):

Answer 30

• Coming out from Craniosacral outflow
• brain stem: CN lll, CN Vll, CN lV, CN X (vagus)
• S_2-S_4 (lowest (sacral) segments )
• Preganglionic nerves are long postganglionic short
• Terminal or Intramural ganglia (next to, on, or in their target organs)
• Release ACh in the interaction and in the target organ, cholinergic neurons

-Constricts pupils, stimulates salvation, constricts airways, slows heartbeat, stimulates digestion, regulates: pancreas, small intestine, bladder, sexual arousal

Question 31

Different pathways for sympathetic neurons:

Answer 31

Route of Preganglionic neuron:

• Lie in intermediolateral gray matter
• Ventral root-> white rami communicans (myalinated)

1) Chain ganglia
- Postganglionic neuron
- >Gray Rami communicans (not myalinated) -> three types of tissues-> Arrector pili, blood vessels, sweat glands

2) Chain ganglia
- Pre ganglionic neuron
- >Descents down to another ganglia level down from the first to chain ganglia
- > Postganglionic neuron -> motor neurons or come out as its own nerve.(splanchnic nerve)

3) Chain ganglia
-> Preganglionic neuron ->
same level to collateral ganglia -> (part of ANS going to abdominal pelvic viscera(sisäelin) -> splanchnic nerve

4) Preganglionic neurons
- >Ascents up to higher level ganglia -> Part of the pylon, pseudo motors etc.

Question 32

Enteric nervous system

Answer 32

• two networks: the myenteric plexus and the submucous plexus.
• contain visceral sensory and motor neurons that control the functions of the digestive organs.
• about 500 million neurons
• operates independently
• Enteric sensory neurons monitor tension and stretch of the gastrointestinal walls, the chemical status of stomach and intestinal contents, and hormone levels in the blood.
• receives input indirectly from the “real” brain via axons of the sympathetic and parasympathetic divisions.

Question 33

Central control of ANS, what and how?

Answer 33

hypothalamus s the main regulator of the autonomic preganglionic neurons
- integrates the diverse information it receives about the body’s status, anticipates(ennakoida) some of its needs, and provides a coordinated set of both neural and hormonal outputs.

• connections of the periventricular zone to the brain stem and spinal cord nuclei=preganglionic neurons of the sympathetic and parasympathetic divisions (jaottelu).
• nucleus of the solitary tract, located in the medulla. The SN projects to, among other regions, the reticular formation (aivoverkosto), parasympathetic preganglionic neurons, hypothalamus and thalamus, forming circuits that contribute to autonomic regulation.

Question 34

cortisol’s tasks

Answer 34

-mobilize energy reserves and suppress the immune system, stress hormone.
(-stimulates gluconeogenesis
-indirect impact in liver and muscle glycogenolyse )
-in brain, cortisol interacts with specific receptors->inhibition of CRH

Question 35

Batterfield trauma victims who have lost large volumes of blood often express a craving to drink water. Why?

Answer 35

Volume decreases-> pressure receptors in cardiovascular system -> vasopressin-containing neurons receive information about changes-> release ADH-> Kidney releases renin-> Liver releases Angiotensinogen, converted to angiotensin 1 by renin->breaks down to angiotensin 2 -> blood pressure increases and also subfornical organ detects this->neurons to hypothalamus and activate cells in lateral area->overwhelming thirst.

Question 36

How has the periventricular zone of hypothalamus orchestrated your body’s physiological response to stressful situation? Describe in detail.

Answer 36

Periventricular zone includes the parvocellular neurosecretory cells in hypothalamus. They communicate with anterior pituitary gland via blood stream. If a stimulus is stressful->release of CRH from hypothalamus to blood stream, blood of portal circulation, short distance to anterior pituitary in 15 seconds->bind to specific receptors on the surface ->release off corticotropin in anterior pituitary->cortisol from adrenal cortex, which mobilize energy reserves and suppress immune system

Question 37

What causes the symptoms of Addisonian crises (weakness, mental confusion, drowsiness, low blood pressure, abdominal pain) and what can be done to treat them?

Answer 37

Adrenal insufficiency causes these symptoms, this means that the release in adrenal cortex has shut down. This again is caused by degeneration of adrenal gland. This can be treated by daily hormone replacement, compensate the loss of cortisol.

Question 38

Why is adrenal medulla often referred to as a modified sympathetic ganglion? Why isn’t the adrenal cortex included in this description?

Answer 38

Epinephrine is released into blood from adrenal medulla. It effects on target tissues almost identical to those caused by sympathetic activation. This is why it is a modified sympathetic ganglion. Adrenal cortex release cortisol, so it is not included to this description.

Question 39

Why does cocaine cause heart failure? How would you explain the peripheral action of cocaine?

Answer 39

Cocaine exert their effects at synapses made by dopaminergic and noradrenergic systems. It causes peripheral effects that mimic activation of the sympathetic division of ANS: increased heart rate and blood pressure. Cocaine targets DA reuptake and thus prolong and strengthen the effects of released DA.

Question 40

How do the diffuse modulatory and point-to-point synaptic communication systems in the brain differ? List four ways.

Answer 40

Diffuse modulatory systems have:

1. Core, each system has a small set of neurons
2. Neurons arise from the central core of the brain, most of them from the brain stem
3. Each neuron can influence many others because each one has an axon that may contact more than 100 000 postsynaptic neurons spread widely across the brain
4. The synapses made by many of these systems release transmitter molecules into the extracellular fluid, so that they can diffuse to many neurons rather than be confined to closeness of synaptic cleft.

Question 41

Under what behavioral condition are the noradrenergic neurons of the locus coeruleus active? The noradrenergic neurons of the ANS?

Answer 41

The neurons in locus coeruleus seems to activate by new, unexpected, nonpainful sensory stimuli in the animal’s environment. In ANS, they activate when sympathetic NS activates, which is most active during crisis.