Diencephalon & Autonomic Nervous System

Objectives Identify all of the subcortical fasciculi and tracts Define projection, commissural, and association fibers For each fasciculus or tract, identify the type of fibers it consists of and

the regions it connects.

Compare and contrast the changes that occur to the different regions of

the cortex throughout a lifespan.

Describe the Anatomy, Blood supply and Functions of Diencephalon

structures:

Thalamus

Hypothalamus & Pituitary Gland

Epithalamus & Pineal Gland

Subthalamus

Thalamus

Thalamus

3 types of nuclei (by function)

Relay nuclei – relays information not involved in a loop

Example: sensory information from face VPM somatosensory

cortex

Association nuclei – nuclei involved in executive functioning

loops

Example: mediodorsal nucleus is involved in the limbic loop (pg

421 LE)

Nonspecific nuclei – receive info from several regions, send info

to entire cortex, involved with alertness and arousal

Example: intralaminar nuclei

Thalamus Blood Supply

Hypothalamus

Hypothalamus 3 zones:

Periventricular zone

oxytocin - intimacy

vasopressin - water retention

Medial zone (3 regions):

Supraoptic region

satiety center – body composition

Suprachiasmatic n. - circadian rhythm

Tuberal region

satiety center – body composition

behavioral center – aggression, rage

Mammillary region

converts short term memory to long term memory (by connections with hippocampus

through fornix)

Lateral zone

involved with satiety

Hypothalamus and Pituitary

It’s Complicated!!

Do NOT need to know

Full list of functions of hypothalamus and pituitary

Growth Blood pressure Some aspects of pregnancy and childbirth including stimulation

of uterine contractions during childbirth Breast milk production Sex organ functions in both males and females Thyroid gland function The conversion of food into energy (metabolism) Water and osmolarity regulation in the body Water balance via the control of reabsorption of water by the 

kidneys Temperature regulation Pain relief

Source: Wikipedia

Hypothalamus Blood Supply

Same as Thalamus!

Epithalamus Pineal Gland

Releases melatonin Collects mineral deposits

Calcium, flouride, phosphorous Blood supply – no BBB!

Posterior Choroidal A.

Subthalamus Involved in motor control Associated with the Basal Ganglia (striatum,

lentiform, PPN, substantia nigra)

Objectives Compare and contrast the sympathetic and

parasympathetic nervous systems (neurotransmitters, receptors and effects)

Describe how afferent information enters the CNS Describe the difference between pre-ganglionic

and post-ganglionic Describe or draw the structure of the sympathetic

trunk Identify and locate the centers that control

respiration, cardiac regulation, and vasomotor regulation

Organization

Neurotransmitters

Receptors Effects

Afferents

Efferents

Anatomy

Control Centers

Symp. Para.

Symp. Para.

Symp. Para. Symp. Para.

Neurotransmitters Cholinergic – all preganglionic, &

postganglionic parasympathetic Adrenergic – postganglionic sympathetic

only Adrenal glands have no postganglionic

neuron – they receive acetylcholine and release adrenaline to bloodstream to stimulate sympathetic activity of all organs

Receptor types vary

Target Organ

SC Ganglia

Discuss With a partner, 2 minutes

What is the significance of pre-ganglionic vs. post-ganglionic? How is this different from the somatic NS?

What systems are adrenaline and noradrenaline used in?

What systems are acetylcholine used in?

Answers Pre-ganglionic is the neuron from the CNS

that ends in a peripheral ganglia Post-ganglionic is the neuron from the

peripheral ganglia that ends in a target organ The somatic NS has no synapses outside the

CNS Adrenaline & Noradrenaline are only in the

Sympathetic NS Acetylcholine is used in parasympathetic,

sympathetic, and somatic systems

Receptors (sympathetic) Adrenergic receptors

(sympathetic on target organs) α1, a2, b1, b2, b3

a1 & a2 receptors constrict blood vessels to skin, viscera, brain, reproductive system, constrict bronchioles

B1 controls pacemaker potential

B2 dilates coronary arteries, arteries to skeletal muscles, dilates bronchioles

Functions (sympathetic)

Receptors (parasympathetic) Muscarinic & Nicotinic receptors

(parasympathetic) No parasympathetic receptors in

uterus a1 cause contraction & b2 cause

relaxation No parasympathetic receptors in

sweat glands, liver, most blood vessels, ventricular muscle

Functions (parasympathetic) Dilate blood vessels to reproductive system

& salivary glands Decreases cardiac output Contracts bronchioles Constricts pupils

Organization

Neurotransmitters

Receptors Effects

Afferents

Efferents

Anatomy

Control Centers

Symp. Para.

Symp. Para.

Symp. Para. Symp. Para.

Visceral Afferents Organ splanchnic

nerves dorsal root ganglion spinal cord solitary nucleus

Collaterals synapse in laminae 5-6 of the spinal cord

Autonomic reflexes

Parasympathetic Anatomy “Craniosacral outflow” Preganglionic somas located in solitary

n., ambiguus, dorsal motor n. of X (medulla), and sacral spinal cord

Vagus nerve and splanchnic nerves contain preganglionic axons

Ganglia are located near target organs

Sympathetic Anatomy “Thoracolumbar outflow” Preganglionic somas located in the lateral

horn Postganglionic somas located in either the

sympathetic trunk/chain or near the target organs

Cervical cardiac and thoracic visceral nerves contain postganglionic axons

Thoracic, lumbar and sacral splanchnic nerves contain preganglionic axons

Sympathetic trunk

Venn Diagram

Conclusion Hypothalamus & Pituitary ANS – parasympathetic vs sympathetic Sensory info from special regulatory

centers directly to Solitary nuc. Receptor types and neurotransmitter

types

Presentations If time – meet with groups