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BCLN BIOLOGY 12 – Rev July 2014

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Unit 13 ~ Learning Guide Name:________________ INSTRUCTIONS Complete the following notes and questions as you work through the related lessons. You are required to have this package completed BEFORE you write your unit test. Do your best and ask questions about anything that you don't understand BEFORE you write the unit test. U13 NOTES: DIVISIONS OF THE NERVOUS SYSTEM AND THE BRAIN (web notes) 1. Central Nervous System

a. Spinal Cord

• Central canal filled with ____________________________________________________.

• Gray matter made up of ________________.

• White matter made of long fibers ___________________________.They are white because they are covered by _________________ _________________.

• The dorsal (back) part of the cord

is specialized to carry _________________ information to the brain.

• The ventral (front) part of the cord sends messages from the _______________________________________.

• __________________________ run together in parallel bundles


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called tracts. Left and right tracts crossover prior to entering the brain. Therefore, left side of the brain controls _______________ of the body and vice versa.

b. Brain Medulla Oblongata:

• Brain Stem (bottom of the brain).

• Pathway between ________ ______________________.

• Controls vomiting, coughing, sneezing, hiccoughing, swallowing.

• Controls: _______________ _____________________________________________________________.

Cerebellum:

• Butterfly shaped. • Rear, lower portion of the

brain. • ____________________

___________ portion of the brain.

• Controls Muscle co-ordination (smooth, graceful motions) _____________________________________________________


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Hypothalamus:

• Located just above the pituitary gland.

• Controls the __________ _____________, hunger, thirst, sleep, body temp, water balance, and BP.

• Maintains homeostasis by controlling endocrine control, Motor control.

Thalamus:

• Above the hypothalamus • Controls ________________________ for information going to the

_________________. Channels info to appropriate place and prevents sensory overload.

Cerebrum:

• __________________ of the brain. • Controls _______________________________, Perceives sensory

information, Initiates movements. • Contains 2 hemispheres (Right and Left). • Memory. • Parts:

i. Frontal Lobe - ____________________________________ ii. Temporal Lobe - __________________________________ iii. Parietal Lobe - ___________________________________

___________________________ iv. Occipital Lobe - Vision.


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Corpus Callosum • Holds the hemispheres of the Cerebrum together. • Conducts impulses from one side of the brain to the other.

At the center of it all is the Central Nervous System. The CNS is comprised of the Brain and the Spinal Cord.

2. Peripheral Nervous System

Is made up of nerves, which are either part of the Somatic or the Autonomic Nervous System.

• ________________: Contains nerves that control skeletal muscles, joints, and skin. They receive and act on external stimuli. Voluntary Control

• ________________: Contains nerves that control the smooth muscles of the internal organs and the glands. Automatic, usually without the need for conscious thought.

• Two Divisions: a. __________________________________ b. __________________________________

Both:

• Function automatically (involuntary). • Serve all internal organs. • Have two motor neurons with a ganglion between


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Adrenal Glands and the Sympathetic and Parasympathetic Divisions Sudden simultaneous release of _________________________ from all the sympathetic neurons (as in times of fright) has a critical effect. It causes the release of the hormone ________________ from the interior of

the _________________________ located on top of the kidneys. The noradrenalin and adrenalin initiate and sustain what is known as the "_____________ ________________" response. They prepare the body to respond to danger in the following ways:

1. ________________________________________________________________ ________________________________________________________________

2. ________________________________________________________________ ________________________________________________________________

3. Sudden contraction of some muscles to tense the body up for action. Included in this is the contraction of the diaphragm. A scared person will gasp, inhaling suddenly.

4. ________________________________________________________________________________________________________________________________

5. Increased blood flow to the skeletal muscles so they are more able to act. 6. ________________________________________________________________

**Note that acetylcholine is the hormone secreted for the parasympathetic system which causes the opposite conditions (see above) in the body as

compared to the sympathetic system**


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Neuroendocrine Control of Bodily Functions There is an association between nerve tissue and the body's hormones (endocrine = hormonal). This association is between the ___________________________________ __________________________________. It can be seen that there are _________ lobes of the pituitary gland: an anterior and a posterior lobe. Both of these extend down from the hypothalamus. As blood passes through the ___________________________, its composition and temperature __________________ various homeostatic responses. These responses involve the release of hormones. The anterior pituitary releases six major hormones that range in effect from bringing about ________________________________________________________________. The posterior pituitary releases ________ hormones. The mechanism of action is slightly different for the release of the anterior pituitary hormones than it is for the posterior pituitary hormones. In the case where the hypothalamus detects that the effect of one of the hormones from the anterior pituitary is required, it releases a hormone-like substance called a releasing factor that travels through the very short blood vessel that is connected with the anterior pituitary. This causes the release of the required hormone.


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In the case of the hormones released by the posterior pituitary, the hypothalamus actually _____________ these hormones which it releases into a nerve tract that conducts them to the ____________________________________________. Regardless of the mechanism, all the hormones are released into the circulatory system and they travel about the body affecting the specific target organs for which they were designed.

**IMPORTANT**

A good understanding of these hormones, where they are produced, what causes their release, where they are released from and the effects they have on the body is extremely important. A good knowledge of these hormones will also

help you in the next two units.


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U13 PRACTICE: DIVISIONS OF THE NERVOUS SYSTEM AND THE BRAIN

1. Identify and briefly describe the two major divisions of the nervous system. (4 marks)

2. Identify and briefly describe the two major divisions of the peripheral nervous system. (4 marks)


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3. The autonomic system has two major divisions:

a. What are the two major divisions called and what are their nicknames? (4 marks)

b. What effect does each branch have on the body? (2 marks)

c. Give a specific example/scenario where each division may be activated. Identify the neurotransmitter that would be released in response to that scenario and list some of the specific effects that the neurotransmitter would have on the body. (6 marks)


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4. Explain how the adrenal glands are involved in the body’s response to stressful situations. (3 marks)

5. Create a flow chart to illustrate the major divisions of the nervous system, including the following terms (9 marks):

o PNS o sympathetic o spinal cord

o autonomic o brain o parasympathetic

o CNS o somatic o nervous system


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6. What is the general function of the brain? (3 marks)

7. Please label the following structures on the diagram below. Please place a brief description of each structure's function beside its label. Please be neat. (14 marks):

o medulla oblongata o cerebellum o hypothalamus

o thalamus o pituitary gland

o corpus callosum o cerebrum


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8. Below is a diagram of the 4 major lobes of the cerebrum. Label each lobe and place a brief description of each lobe's function beside its label. Please be neat. (8 marks):


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~ END OF BIOLOGY 12 UNIT 13 LEARNING GUIDE ~

UNIT 13 ANSWER KEY U13 PRACTICE: DIVISIONS OF THE NERVOUS SYSTEM AND THE BRAIN

1. Identify and briefly describe the two major divisions of the nervous system. (4 marks) = central nervous system including brain and spinal cord for receiving and integrating information from peripheral nervous system and directing responses to internal and external stimuli

= peripheral nervous system is essentially all the nerves excepting those of the brain and spinal cord and it is responsible for detecting external and internal stimuli and transmitting the information to the central nervous system where it is then integrated to direct a response that is then transmitted via the peripheral nervous system to effectors

2. Identify and briefly describe the two major divisions of the peripheral nervous system. (4 marks) = sensory (afferent) neurons that detect internal and external stimuli and transmit the information to the central nervous system

= motor (efferent) neurons that carry signals from central nervous system to effectors to initiate a response to stimuli

3. The autonomic system has two major divisions: a. What are the two major divisions called and what are their nicknames? (4 marks)

= sympathetic (fight-or-flight) = parasympathetic (=rest-or-digest)

b. What effect does each branch have on the body? (2 marks)

= sympathetic prepares the body for danger or activity such as increasing heart rate, breathing rate, dilating pupils, sending blood to skeletal muscles and away from intestines, limiting digestion

= parasympathetic prepares the body for recovery/rest such as decreasing heart rate, breathing rate, constricting pupils, sending blood to digestive system and away from skeletal muscles, enhancing digestion


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c. Give a specific example/scenario where each division may be activated. Identify the neurotransmitter that would be released in response to that scenario and list some of the specific effects that the neurotransmitter would have on the body. (6 marks)

= sympathetic might be activated in situations of stress such as during a test or before a big game/performance or when frightened, it will cause the nervous system to release norepinephrine (noradrenalin) which will lead to increased heart rate, breathing rate, dilating pupils, sending blood to skeletal muscles and away from intestines, limiting digestion = parasympathetic might be activated after periods of stress, when relaxing in savasna (for the yogis out there), it will cause the release of acetylcholine which will lead to decreased heart rate, breathing rate, constricting pupils, sending blood to digestive system and away from skeletal muscles, enhancing digestion

4. Explain how the adrenal glands are involved in the body’s response to stressful situations. (3 marks)

In situations of stress sympathetic neurons release noradrenalin (aka norepinephrine) which then cause the adrenal glands to release adrenalin (epinephrine) which initiates the flight-or-fight response including increase heart and breathing rates, dilated pupils, dilated airways, increased blood flow to skeletal muscles, decreased blood flow to digestive system, and decreased saliva secretion (hence dry mouth when stressed).

5. Create a flow chart to illustrate the major divisions of the nervous system, including the following terms (9 marks):

o PNS o sympathetic o spinal cord

o autonomic o brain o parasympathetic

o CNS o somatic o nervous system


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6. What is the general function of the brain? (3 marks) = to receive and process/integrate sensory information, to direct responses to such information, to store and retrieve memories of such information, to use such information to determine future responses

7. Please label the following structures on the diagram below. Please place a brief description of each structure's function beside its label. Please be neat. (14 marks):

o medulla oblongata o cerebellum o hypothalamus

o thalamus o pituitary gland

o corpus callosum o cerebrum

Medulla oblongata = respiratory and cardiac control centers, involuntary responses such as coughing, sneezing, hiccupping, vomiting

Cerebellum = balance and coordinated/graceful movement

Hypothalamus = maintain homeostasis such as temperature, hunger, thirst, sleep, water balance, control the pituitary gland

Thalamus = relay station that passes on important signals to the cerebrum

Pituitary gland = storing and producing hormones such as human growth hormone

Corpus callosum = physical and electrical bridge linking the right and left hemispheres of the brain


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Cerebrum = largest portion of human brain that is involved in conscious thought, perceiving sensory information and initiating movement

8. Below is a diagram of the 4 major lobes of the cerebrum. Label each lobe and place a brief description of each lobe's function beside its label. Please be neat. (8 marks):


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