1 nervous system ii- the brain, cranial nerves & autonomic nervous system rev 3-11 the brain is...

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Nervous System II-The Brain, Cranial Nerves

& Autonomic Nervous System REV 3-11

• The brain is organized into areas to make studying its function easier.

• The forebrain includes the cerebrum and diencephalon (the hypothalamus, thalamus,& limbic system)– This area is responsible for receiving and

integrating sensory input from the external environment and determines most of our complex behavior

BIO Lab 102 Lec 6-Nervous II

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Nervous System II-the brain

• The midbrain includes the corpora quadrigemina– helps coordinate muscle groups and responses

to sights and sounds• The hindbrain includes the medulla, pons and

cerebellum– coordinates automatic and vital tasks


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Nervous System II-Cerebrum Lec 6

• Cerebrum (figure 9.1, page 73 lab manual)

– is the largest, most superior and anterior part of the brain

– is divided into left and right “cerebral hemispheres” by the longitudinal fissure

– each hemisphere controls the opposite side of the body


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– In the middle of the hemispheres is the corpus callosum which enables the 2 hemispheres to communicate and share sensory and motor information

• Below the corpus callosum in each hemisphere are the lateral ventricles which secrete CSF

– The outer layer of the cerebrum is called the cerebral cortex and is primarily gray matter

– The inner portion of the cerebrum is primarily white matter


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– surface tissue of the cerebrum is covered with sulci (grooves) and gyri (ridges) which increase the surface area for information exchange

– Each hemisphere is further divided into 4 lobes: the frontal, parietal, temporal, and occipital lobes

– all 4 lobes are involved in memory storage


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Nervous System II- Lec 6

– The frontal lobes, located in the forehead area, initiate motor activity and are responsible for speech and conscious thought

• these lobes may be further divided into the prefontal lobes or cortex (the most forward area of these lobes) which are the intellectual center

– intelligence, motivation, personality, abstract reasoning, judgment, planning, love, concern for others

• the premotor cortex – skilled repetitive activities (typing) and conditioned

reflexes (Pavlov’s dog)BIO Lab 102 Lec 6-Nervous II

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Nervous System II -Frontal lobesLec 6

• the primary motor cortex which initiates voluntary motor activity of the arms, legs, trunk and face

• In the dominant hemisphere only is Broca’s area which is our primary speech center

– Broca’s area controls the speech muscles – The parietal lobes, located behind the frontal lobes in

approximately the middle third of the cerebrum, house the sensory, or somatosensory, cortex

• interpret sensory information from the skin and from proprioceptors in the muscles and joints.

• integrate different sensory inputs to allow us to interpret sensory information


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Nervous System II Lec 6-Occipital lobes

– The occipital lobes are located in the back of the head (just before the neck area)

– house the primary visual cortex and the visual association area (association areas allow us to interpret/understand information)


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Nervous System II Lec 6 -Temporal Lobes

– The temporal lobes, located on the sides of the head, house the primary auditory cortex• auditory association area, including spoken

and written language interpretation, and auditory memory

• if damaged, we suffer from aphasia (Wernicke’s or receptive aphasia, Broca’s or expressive aphasia)

• also includes the olfactory cortex (sense of smell)


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Nervous System II Lec 6 -Diencephalon

• The Diencephalon is located above the midbrain and under the cerebrum– it includes the thalamus, hypothalamus and

pineal gland– Thalamus: is a receiving, processing and

transfer center. It receives sensory signals from other parts of the brain and the body and routes them to the appropriate parts of the brain for interpretation.


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– Hypothalamus: regulates the activities of the autonomic nervous system and regulates endocrine function including the pituitary gland;

Also• regulates the limbic system--the emotional

part of the brain.– Also responsible for short term memory


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• Pineal Gland or Epithalamus: – secretes the hormone melatonin.– regulates the onset of sexual maturation and

serves as a biological clock• fibers from the eye go to the pineal body and let you

know when it’s daytime/nightime

• Pituitary Gland: often called the master gland because it controls many other glands

• Optic Chiasm: formed by the crossing of the 2 optic nerves


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Nervous System II Lec 6 -the Midbrain

• The Midbrain--conduction pathway between higher and lower brain centers– has some control over alertness

– controls movement of the eyes and pupil size

– houses the corpora quadrigemina, a reflex center for the movement of the head in response to visual and auditory stimuli

– monitors the unconscious movement of skeletal muscles so their actions are smooth and coordinated

– contains part of the reticular activating system

• RAS controls our levels of sleep and wakefulness


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The Hindbrain or Brain Stem• includes the medulla, pons, and cerebellum

Medulla• contains areas that control vital automatic

functions of internal organs– cardiac center-adjusts the force and rate of heart

contraction to meet the body’s needs

– vasomotor center-regulates blood pressure by acting on smooth muscle in the walls of blood vessels to constrict or dilate

– respiratory center-controls rate and depth of breathing

– other centers which regulate vomiting, hiccuping, swallowing, coughing and sneezing


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– Pons• connects the higher brain centers and the

spinal cord• its respiratory nuclei work with the

respiratory centers of the medulla to control respiratory rate and depth

• coordinates the information flow between the cerebellum and higher brain centers


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Nervous System II Lec 6 -Hindbrain/Brain Stem

– Cerebellum• processes information from various parts of

the brain to allow smooth, coordinated, skilled movements

– excessive alcohol disrupts normal functioning of the cerebellum; this is why drunk people lose the ability to coordinate their movements including walking a straight line

– contains the arbor vitae (white matter) which looks like a branching tree


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Nervous System II Lec 6

• Cranial Nerves

– there are 12 pairs of cranial nerves

(this is all we will do relating to the Cranial Nerves since it is primarily a lecture topic.)

• The Autonomic Nervous System (ANS) is also referred to as the involuntary nervous system

– we generally cannot voluntarily control activities which this system regulates

– this division regulates the activity of smooth muscles, cardiac muscles, and glands


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• The ANS can be further divided into the– the sympathetic nervous system (SNS) which

mobilizes body systems during emergency situations

• called the fight or flight division

• nerves emerge from the thoracic and lumbar segments of the spinal cord (also called the thoracolumbar area)

• releases the neurotransmitters epinephrine and norepinephrine


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– the parasympathetic nervous system (PNS) which primarily conserves our energy use

• considered to be the “normal function” division- -it keeps our body functioning under normal, non-stressful conditions

• the nerves emerge from the brain and sacral regions of the spinal cord

• releases the neurotransmitter acetylcholine which has an opposite effect from the SNS neurotransmitters


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Reminder, page 1of 2: Lec 6

1. There is a supplementary color handout for the sheep brain. Each table should have 1-4 copies. DO NOT take these home.

2. Use the models to learn parts of the human brain in the bulleted lists on pages 76 and 77.

3. For the sheep brain, use the handouts as your guide. Learn only the items labeled in the handout. You will not be doing actual dissection since this has already been done.


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Reminder, page 2 of 2: Lec 6 Nervous System II

4. Skip specifics of cranial nerves in figure 9.5 and table 9.1.

5. Learn general aspects of the Autonomic Nervous System using figure 9.6 in the lab book.


1 nervous system ii- the brain, cranial nerves & autonomic nervous system rev 3-11 the brain is...

Documents

nervous iibio lab

cerebrum lec

lab manualis

bodybio lab

sensory informationbio

vital tasksbio lab

memory storagebio lab

white matterbio lab