1. NOTES: CH 49 - NERVOUS SYSTEM ORGANIZATION; THE HUMAN BRAIN

2. Recall…the nervous system is divided into 2 divisions:
● CENTRAL NERVOUS SYSTEM (CNS): information processing; integration ● PERIPHERAL NERVOUS SYSTEM (PNS): transmits info. to/from the CNS; plays a large role in regulating an animal’s movement & internal environment

4. Organization of the CENTRAL NERVOUS SYSTEM:
● consists of the BRAIN & SPINAL CORD
● BRAIN: integration; complex behavior
● SPINAL CORD: conveys info. to / from the brain; generates basic patterns of locomotion

5. SPINAL CORD:
● can also act independently of the brain as part of simple nerve circuits: REFLEXES! ● a reflex protects the body by triggering a rapid, involuntary response to a particular stimulus ● EXAMPLE: knee-jerk reflex

7. Organization of the CENTRAL NERVOUS SYSTEM:
● CEREBROSPINAL FLUID:
-formed in the brain by filtration of blood
-circulates through brain, providing nutrients & hormones; carries away wastes
-cushions the brain & spinal cord

8. GRAY & WHITE MATTER:
● GRAY MATTER: -consists mainly of neuron cell bodies, dendrites, unmyelinated axons, & glia (support cells) ● WHITE MATTER: -consists of bundled axons w/myelin sheaths (gives the white appearance)

9. Organization of the PERIPHERAL NERVOUS SYSTEM:
● consists of NERVES that branch out from the CNS and connect it to other parts of the body.
● includes:
SPINAL NERVES and CRANIAL NERVES

10. CRANIAL NERVES ● mammals have 12 pairs of cranial nerves
● originate from the cerebrum & brain stem
● innervate parts of the head, neck and trunk

11. CRANIAL NERVES

12. SPINAL NERVES ● mammals have 31 pairs of spinal nerves
● originate from the spinal cord
● innervate the upper & lower limbs, neck, and trunk

13. SPINAL NERVES

14. PERIPHERAL NERVOUS SYSTEM (PNS):
● can be subdivided into the:
1) Motor system: oversees conscious (voluntary) activities (i.e. skeletal muscles);
2) Autonomic nervous system: controls unconscious (involuntary) activities (i.e. heart, stomach, intestines, glands)

17. AUTONOMIC NERVOUS SYSTEM
● branch of the PNS that is involuntary;
● includes 2 subdivisions:
1) SYMPATHETIC DIVISION;
2) PARASYMPATHETIC DIVISION.

19. ● Sympathetic and parasympathetic divisions may act antagonistically (in opposition), alternately activating or inhibiting the actions of some organs, glands, etc.

20. SYMPATHETIC DIVISION:
● prepares the body for energy-expending, stressful, or emergency situations
EXAMPLE: during an emergency, the sympathetic division will increase the heart rate and breathing rate, etc.

22. PARASYMPATHETIC DIVISION:
● is most active under ordinary, restful conditions;
● counterbalances the effects of the sympathetic division
EXAMPLE: after an emergency, the parasympathetic division decreases the heart rate, breathing rate, etc.

27. Parts of the Brain:
● During embryonic development, 3 brain regions become evident:
FOREBRAIN
MIDBRAIN
HINDBRAIN

31. Brain Regions: ● Forebrain includes: cerebrum, thalamus, hypothalamus
● Midbrain
● Hindbrain includes: pons, medulla oblongata, cerebellum
**the midbrain, along with the pons and medulla oblongata form the BRAINSTEM

34. BRAINSTEM:
● anterior end of
spinal cord;
● 3 parts that
function in:
-homeostasis
-movement coordination
-conduction of info. to higher
brain centers:

35. BRAINSTEM:
3 parts of the brainstem: 1) Medulla oblongata 2) Pons 3) Midbrain

37. 1) Medulla oblongata: controls breathing, heart and blood vessel activity / dilation (and therefore blood pressure), respiratory center, swallowing, vomiting, digestion

38. 2) Pons: regulates
breathing centers in
the medulla; relays
impulses between the
cerebrum and the
medulla, and the
cerebrum and
cerebellum.

40. 3) Midbrain:
● receives and sends sensory information;
● coordinates visual reflexes (eye movements with other movements)
● coordinates auditory reflexes (move the head to hear a sound more distinctly)

41. CEREBELLUM:
● coordination of movement;
● balance;
● hand-eye coordination

43. THALAMUS:
● relay center that sorts out & transmits sensory information to and from cerebrum;
● incoming information from all the senses is sorted here and sent on to the appropriate higher brain center;
● involved in regulating emotion
& arousal (wakefulness)

45. HYPOTHALAMUS:
 important regulator of HOMEOSTASIS
 contains body’s thermostat
 includes centers for regulating hunger & thirst
 plays role in sexual response and mating behavior

47. HYPOTHALAMUS:
fight-or-flight response, pleasure, daily biorhythms (“biological clock”)
source of posterior pituitary hormones & releasing hormones for anterior pituitary hormones

52. CEREBRUM:  divided into hemispheres (R and L)
 each hemisphere divided into lobes (frontal, parietal, temporal, occipital)
 each hemisphere has an outer covering of gray matter = CEREBRAL CORTEX
 hemispheres are connected by white matter called CORPUS CALLOSUM

55. CEREBRUM – functions!  where memories are stored
interprets sensory impulses arriving
from sense organs
 centers for motor coordination; send motor impulses to muscles
 where conscious decisions are made
intelligence and personality stem from cerebral activity
language, cognition / thought / problem solving

60. There are 2 functional cortical areas:
1) Primary Motor Cortex: sends commands to skeletal muscles, signaling appropriate responses to sensory stimuli

63. 2) Primary Somatosensory Cortex:
 receives and integrates signals from touch, pain, pressure, and temperature receptors;
 divided into specific areas so that we can associate specific stimuli with specific parts of the body. 

66. Nervous System Disorders:
● Schizophrenia ● Depression ● Bipolar disorder (manic-depressive) ● Drug addiction ● Alzheimer’s Disease ● Parkinson’s Disease

67. Schizophrenia:

68. Drug
Addiction: