Quiz 2 (suzanne's) Flashcards
What structure is located under the cerebrum and above the brain stem?
Diencephalon
What is RAS?
Reticular Activating System
- It projects sensory axons to the cerebrum.
- RAS is important in maintenance of consciousness, awakening from sleep, autonomic reflexes: heart rate,blood pressure.
- RAS is, probably, involved in pain relief as well.
Was does RAS do?
- projects sensory axons to the cerebrum.
- maintenance of consciousness, awakening from sleep
- autonomic reflexes: heart rate, blood pressure.
- probably, involved in pain relief as well.
What is reticular formation?
Net-like mesh of neuron bodies (soma) and axons.
- Extends from the upper part of the spinal cord to the diencephalon via brain stem
- Has both sensory and motor parts
What does the troclear nerve do (cranial nerve IV)?
- Controls Superior Oblique Eye Muscle
- Moves the eye ball medially and down
What does cranial nerve III (oculomotor) do?
- Controls all extra-ocular muscles but lateral rectus and superior oblique mm.
- Moves eye medially, up, down, elevates the upper lid.
- pupil constriction–lens accommodation for near vision (pupillary and accommodation reflexes)
What is Periaqueductal (central) gray?
Neuron cluster, surrounding the cerebral aqueduct
- part of Reticular Formation
- “Grand Central” of all sensory and motor tracts along the brainstem.
- Periaqueductal gray is important in pain perception and pain modulation
Where is the substantial nigra?
At the base of each cerebral peduncle.
-Functionally part of basal ganglia.
What is the superior coliculli.
- reflex centers for vision (eye tracking of moving objects; eye scanning of stationary images/ reading)
- adjustment of the pupil size and lens shape (pupilary and accommodation reflexes)
- reflexes of a corresponding eye, head, and neck movement
What is the inferior colliculi?
Part of the auditory pathway/ tract
-Originate and control reflex for sudden head / body movement, when one is
startled or surprised.
What are the cerebral peduncles?
They represent the anterior part of the midbrain.
- Hold and Support cerebral hemispheres, like two pillars.
- Tracts which connect the cerebrum with the pons, medulla oblongata and spinal cord.
- At their base substantia nigra.
What are major S/S of Parkinson’s disease?
Resting tremor
Bradykinesia–slowness mvmt
Hypokinesia–decreased mvmt
Muscular rigidity
Delayed initiation and termination ofmovements
Dementia / Loss of content of consciousness
The Midbrain (Mesencephalon)
Situated between the pons and diencephalon (everything with the root “thalamus”).
-Contains nuclei and tracts.
-Divided on posterior and anterior parts by the cerebral aqueduct (pathway for
cerebro-spinal fluid or CSF from 3rd to 4th ventricle)
What is RF?
Reticular formation
Where is the Subthalamus located?
Situated under the thalamus (“like a saucer plate under the saucer”)
Consists of tracts and a pair of subthalamic nuclei
What is Cranial Nerve IV?
Troclear nerve
What does the subthalamus do?
It coordinates movement (Along with Red nuclei and Substantia nigra of
the midbrain)
If injured: violent ballistic movements. Involuntary violent mvmts.
(hemiballismus) could develop on the opposite site of the lesion.
Thalamus
Two oval- shaped nuclei: one in each hemisphere
Connected by the intermediate mass
80% of the diencephalon
Major SENSORY and motor relay/ switch center
Surrounded by Basal Ganglia and LimbicSystem nuclei
What are the functions of the thalamus?
Major relay station for sensations of touch, taste, smell, visual, auditory, and temperature from the body to the brain cortex
Relays motor commands between the cerebellum, basal ganglia and cerebrum
Relays impulses within the cerebral cortex for planning and execution of movement
Contributes to autonomic function regulation of”Zang/ Fu” organs (cardiac
What is the oculomotor?
Cranial nerve III
Hypothalamus
Located inferior and anterior to the thalamus
It is a conglomerate of multiple nuclei
Forms the roof and ventro-lateral walls of the third ventricle
Has connections with the pituitary, limbic system, thalamus, autonomic nervous system and other parts of the brain
Major center of homeostasis regulation
Endocrine system’s control starts here
Hypothalamus is in charge of temperature, reproduction, libido, hunger and thirst, sleep/wake, emotions, endocrineregulation
Supra optic: hypothalamic nuclei
Situated above the optic nerve.
Regulates blood pressure and blood volume
Secretes ADH (Anti-Diuretic Hormone) via axons
Posterior Pituitary (AKA Neurohypophysis) via vessels of hypophyseal portal system into the blood circulation Kidney water conservation
The stimulus for supraoptic nucleus: increase of the blood osmolarity
Paraventricular Nucleus
Secretes the hormone Oxytocin
Oxytocin is needed as per contraction of the uterine muscle to expel a product of conception; for contraction of smooth muscle of the breast milk ducts during breast feeding
Anterior and PosteriorHypothalamic Nuclei
Overall setting of a “Thermostat” for the temperature control and a Fever execusion, when needed.
What is the pineal gland?
The endocrine gland: secretes melatonin (sleep hormone) and serotonin (“comfort” neurotransmitter/ hormone). Also secretes CCK.
What does arcuate nucleus do?
Hormones that affect endocrine.
Produces major regulatory hypothalamichormones, regulating anterior pituitary (Adenohypophysis) activity: - TRH - GHRH - GnRH - CRH - Somatostatin - PIF
Lateral and Medial Preoptic Nuclei
Produce Regulatory Reproductive Hormones (Gonadotropin Releasing Factors)
Stimulate Anterior Pituitary (AKA Adenohypophysis) to produce LH and FSH
Participate in temperature regulation along withanterior and posterior hypothalamic nuclei and other autonomic activities
Associations
Connect neurons within the same hemisphere.
Association areas are responsible for more complex functions: memory, emotions,
judgment, personality, intelligence
What are the three cerebral connections?
Commisures
Association
Projections
Where are the axons of the substantia nigra projected?
The basil ganglia.
What is the substantia nigra rich in.
The chemical neurotransmitters malanin and dopamine.
What happens if substantia nigra is injured or degenerated?
(Parkinsonism), uncontrolled body shaking, along with other movement coordination, and posture abnormalities will develop.
Area 4?
Primary motor area. Major motor neurons.
Precentral gyrus in frontal lobe.
VOLUNTARY MVMT.
Area 6?
Premotor area.
Immediately anterior to primary area. Connected to #4.
Learned motor activities. Complex, sequential, more refined mvmts.
Area 8?
Frontal eye field area. Frontal cortex.
Voluntary scanning, mvmt of the eyes.
Areas 41, 42?
Primary auditory area.
Superior part of temporal lobe. Near lateral cerebral sulcus.
Receives information for sound. Auditory perception.
The Limbic System
Ring of tissue on medial surfaces of cerebrum; evolutionary- the oldest part of the brain
Two major functions:
producing emotional aspects of behavior
storing and transformation of new memories (moving ideas, feelings, sensations from the short-term to the long-term memories.
Amygdala
gratification. Sex and food. If amg is excessive or overreacting people exibit antisocial behavior. Become more violent.
Hippocampus
It belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. Humans and other mammals have two hippocampi, one in each side of the brain. The hippocampus is a part of the cerebral cortex; and in primates it is located in the medial temporal lobe, underneath the cortical surface. It contains two main interlocking parts: Ammon’s horn[1] and the dentate gyrus.
Basal Ganglia: Functions
Control/ help in initiation and termination of movements.
Putamen controls body automatic movement;
Caudate nucleus -eye movements;
Globus pallidus regulates muscle tone for specific body movements.
Control of subconscious contractions of skeletal muscles (ex., swinging, when walking, smiling, when joyful, etc.)
Control of initiation/termination of some cognitiveprocesses (attention, memory, planning, emotional behavior).
Basil ganglia
Masses of gray matter (nuclei) deep within each cerebral hemisphere.
Two next to each other clusters of nuclei, lateral and surrounding the Thalamus
- Globus pallidus (pale ball or globe): closer to the thalamus
- Putamen (shell)- more lateral next to GP
- Caudate nucleus (tail- shaped) with the head, body and tail
What is the the tectum (roof)?
Posterior part of the midbrain.
What does the tectum consist of?
Inferior and superior coliculli.
What does the Epithalamus consist of?
Pineal gland and Habenular Nuclei.
What is The Habenular Nuclei
responsible for an emotional aspect of smell (“ I like her perfume: It smells like my Mom’s”).
What does the subthalamus do?
Coordinates movement.
What is the Major SENSORY and motor relay/ switch center? (Synaptic areas)
Thalamus.
Thalamic Nuclei: Anterior nucleus
responsible for emotions, memory, alertness
Thalamic nuclei: Lateral Geniculate
(“knee- shaped”): relay for visual impulses
Thalamic nuclei: Medial Geniculate
relay for auditory impulses
What is the major center for homeostasis regulation?
Hypothalamus
What is the stimulus for the supraoptic nucleus?
An increase in the Blood osmorality
What secretes the hormone oxytocin
Paraventricular nucleus
What cools you?
Anterior hypothalamic nucleus.
What warms you?
Posterior hypothalamic nucleus.
What is responsible for circadian rythmn?
Suprachiasmatic Nucleus
Ventromedial
Stop eating
Dorsomedial
I’m so hungry. Stimulates appetite.
What is considered the seat of intelligence? Or site of conscious thought?
The cerebrum
Commisures
Connect left and right hemispheres. Major one is corpus callosum.
Projections
Connect cerebral neurons with the spinal cord
Corpus callosum
Major commisure. Connection between GitHub and left hemispheres.
What does the central sulcus separate?
Frontal lobe and parietal lobe.
What are the 5 lobes?
Frontal, parietal, temporal, occipital, insula
The diencephalon consists of what parts?
Epithalamus
Thalamus
Hypothalamus
Subthalamus
What is the Vertical sequence of the brain parts?
Cerebrum • Diencephalon • Brainstem * Midbrain Cerebellum: * Pons posterior to * Medulla oblongata the brainstem
