CHAPTER 13 - Central Nervous System - Part 2

What are the three parts of the diencephalon?

– Thalamus, Hypothalamus, Epithalamus

What does the thalamus act as?

A relay station for information going to the cerebral cortex

What does the thalamus do with ascending input?

Sorts, edits, and relays sensory and motor information

What types of impulses does the thalamus receive?

From hypothalamus (emotion/visceral function), cerebellum/basal nuclei (motor), and sensory areas (memory integration)

What are the main functions of the thalamus?

Mediate sensation, motor activities, cortical arousal, learning, and memory

What is the nickname of the hypothalamus?

Mob boss

What is the hypothalamus located below?

The thalamus

What structure connects the hypothalamus to the pituitary gland?

Infundibulum

What paired nuclei in the hypothalamus act as olfactory relay stations?

Mammillary bodies

What is the main role of the hypothalamus?

Maintains homeostasis and regulates visceral functions

Which system is the hypothalamus a part of?

The limbic system

What are some autonomic functions controlled by the hypothalamus?

Blood pressure, heart rate, digestion, pupil size

What physical responses to emotions does the hypothalamus initiate? 

Pleasure, fear, rage, biological rhythms, and drives

What does the hypothalamus regulate to maintain body homeostasis?

Body temperature, hunger, thirst, and sleep-wake cycles

Which hypothalamic nucleus sets the biological clock?

Suprachiasmatic nucleus

What gland does the hypothalamus control through hormone release?

The pituitary gland

What happens if the hypothalamus is damaged?

Can cause body wasting, obesity, sleep issues, dehydration, or emotional imbalance

What part of the diencephalon forms the roof of the third ventricle? 

Epithalamus

What gland is found in the epithalamus?

Pineal gland

What does the pineal gland secrete?

Melatonin

What does melatonin regulate?

Sleep-wake cycle

What are the three parts of the brain stem?

Midbrain, Pons, Medulla oblongata

What functions does the brain stem control?

Automatic behaviors that are necessary for survival.

How many cranial nerves originate from brain stem nuclei? 

10 of 12

What are the two ventral bulges of the midbrain called?

Cerebral peduncles

What connects the third and fourth ventricles in the midbrain?

Cerebral aqueduct

What midbrain region plays a role in pain suppression and the fight-or-flight response?

Periaqueductal gray matter

What paired dorsal structures in the midbrain form visual and auditory reflex centers?

Corpora quadrigemina

What are the two parts of the corpora quadrigemina?

Superior colliculi (visual reflexes) and inferior colliculi (auditory relay)

What midbrain structure is linked to Parkinson’s disease?

Substantia nigra

What is the function of the red nucleus?

Relay nuclei for limb flexion motor pathways

What cranial nerves originate from the pons?

V (trigeminal), VI (abducens), VII (facial)

What function does the pons assist with?

Helps maintain breathing rhythm

What connects the medulla oblongata to the spinal cord?

Foramen magnum

What ventricle is found in the medulla oblongata?

Fourth ventricle

What structure in the medulla forms cerebrospinal fluid?

Choroid plexus

What are the ventral ridges on the medulla called?

Pyramids

What occurs at the decussation of the pyramids?

Motor tracts cross to the opposite side of the body

What are the inferior olivary nuclei responsible for?

Relaying stretch information from muscles and joints to cerebellum

What cranial nerves originate from the medulla?

VIII Vestibulocochlear, IX Glossopharyngeal, X Vagus, and XII Hypoglossal

What are the two sensory relay nuclei in the medulla?

Nucleus cuneatus and nucleus gracilis

What is the medulla’s main role? 

Acts as an autonomic reflex center

Which higher structure does the medulla relay instructions from?

Hypothalamus

What are the cardiovascular centers of the medulla?

Cardiac and vasomotor centers

What does the cardiac center regulate?

Force and rate of heart contraction

What does the vasomotor center regulate?

Blood vessel diameter and blood pressure

What do the respiratory centers in the medulla control?

Rate and depth of breathing

What other reflexes are controlled by the medulla?

Vomiting, hiccupping, swallowing, coughing, sneezing

What percentage of brain mass does the cerebellum make up? 

About 11%

Where is the cerebellum located?

Dorsal to the pons and medulla

What are the main functions of the cerebellum?

Coordinate movement, balance, and posture

What inputs does the cerebellum process?

From the cerebral cortex, brain stem, and sensory receptors

What pattern does white matter in the cerebellum form?

Arbor vitae

What connects the two cerebellar hemispheres?

Vermis

What are the three cerebellar lobes?

Anterior, posterior, and flocculonodular

What does the cerebellum compare during movement?

Intended movement vs actual performance

What is the first step in cerebellar processing?

Receives impulses from the cerebral cortex to start voluntary muscle contraction

What is the second step in cerebellar processing?

Receives body position signals from proprioceptors and visual/equilibrium pathways

What is the third step in cerebellar processing?

Calculates best way to coordinate muscle contraction

What is the fourth step in cerebellar processing?

Sends “blueprint” for movement to motor cortex and brain stem

What other cognitive functions does the cerebellum assist in?

Thinking, language, and emotion

What are functional brain systems?

Networks of neurons working together across multiple brain regions

What are the two major functional brain systems?

Limbic system and Reticular formation

Where is the limbic system located?

Medial aspects of cerebral hemispheres and diencephalon

What is the main role of the limbic system?

Emotion and memory

What does the amygdaloid body do?

Recognizes fear/anger, assesses danger, and triggers fear responses

What does the cingulate gyrus do?

Expresses emotions via gestures and resolves mental conflict

What emotional reaction is linked to the limbic system?

Emotional responses to odors (e.g., skunks smell bad)

Which brain region relays most limbic system output?

Hypothalamus

How does the limbic system interact with the prefrontal cortex?

Links emotions with conscious understanding

Which limbic structures are key to memory formation?

Hippocampus and amygdaloid body

What type of illnesses can the hypothalamus cause when linked to the limbic system?

Psychosomatic illnesses

Where is the reticular formation located?

Extends through the central core of the brain stem

What are the three columns of the reticular formation?

Raphe nuclei, medial group, and lateral group

What parts of the brain is the reticular formation connected to?

Hypothalamus, thalamus, cerebral cortex, cerebellum, and spinal cord, medulla oblongata, pons

What system keeps the brain alert and conscious?

Reticular activating system (RAS)

What percentage of weak stimuli does the RAS filter out?

About 99%

What inhibits the RAS?

Sleep centers, alcohol, and drugs

What can severe damage to the RAS cause?

Permanent coma

What is the motor function of the reticular formation?

Helps control coarse limb movements

What visceral functions are regulated by reticular autonomic centers?

Vasomotor, cardiac, and respiratory centers

What are examples of higher mental functions?

Language, memory, brain waves, consciousness, and sleep

Where is the language system primarily located?

Left hemisphere

What area of the brain is responsible for speech production?

Broca’s area

What happens with a lesion in Broca’s area?

Person understands words but cannot speak

What area of the brain is responsible for language comprehension?

Wernicke’s area

What happens with a lesion in Wernicke’s area?

Person can speak but words make no sense

What is the function of the corresponding right hemisphere areas?

Handle nonverbal language components (tone, gestures, emotion)

What is memory?

The storage and retrieval of information

What are the four types of memory?

Declarative, procedural, motor, and emotional

What does declarative memory store?

Facts (names, faces, words, dates)

What does procedural memory store?

Skills (like playing piano)

What does motor memory store?

Motor skills (like riding a bike)

What does emotional memory store?

Experiences linked with emotion

What are the two stages of declarative memory?

Short-term memory (STM) and long

How many pieces of information can STM hold?

About seven or eight

Which stage of memory has limitless capacity?

Long-term memory (LTM)

What factors affect transfer from STM to LTM?

Emotional state, rehearsal, association, automatic memory

Which brain regions are involved in memory consolidation?

Hippocampus, temporal cortex, thalamus, and prefrontal cortex

What is anterograde amnesia?

Loss of ability to form new memories