1. Chapter 49
Nervous Systems

2. 3 overlapping functions:
The nervous system is a combination of electrical & chemical signals that enable nerve cells to communicate with each other.
3 overlapping functions:
__________
conduction of signals (light, smell) from sensory receptors to integration centers

3. __________
process by which the information from the environmental stimulation of the sensory receptors is interpreted and associated with appropriate responses of the body
Integration is carried out in the Central Nervous System (CNS) (brain & spinal cord in vertebrates)
3. __________
conduction of signals from the integration center to effector cells that actually carry out the body’s responses to stimuli
Signals are conducted by nerves.
Sensory input and Motor output are carried out in the Peripheral Nervous System (PNS)

4. Overview of a vertebrate nervous system

5. The spinal cord conveys information from the brain to the PNS
The __________ also produces reflexes independently of the brain
A __________ is the body’s automatic response to a stimulus

6. Nervous system is composed of:
__________
(nerve cell) functional unit of the nervous system
transmits signals from one location in the body to another
__________– convey nerve impulses toward the cell body
__________– convey nerve impulses away from the cell body
provide structure
protect, insulate and assist neurons

7. Figure 48.2 Structure of a vertebrate neuron

8. Nervous systems:
1. A nerve net is a series of interconnected nerve cells
Sea stars have a nerve net in each arm connected by radial nerves to a central nerve ring
More complex animals have nerves (bundles that consist of the axons of multiple nerve cells)

9. (b) Sea star (echinoderm)
Fig. 49-2a
Radial
nerve
Nerve
ring
Nerve net
Figure 49.2a, b Nervous system organization
(a) Hydra (cnidarian)
(b) Sea star (echinoderm)

10. 3. Nerve Cord
thick bundle of nerves usually extending through the body from the brain
4. Cephalization is the clustering of sensory organs at the front end of the body (anterior)
Relatively simple cephalized animals, such as flatworms, have a central nervous system (CNS)

11. (c) Planarian (flatworm) (d) Leech (annelid)
Fig. 49-2b
Eyespot
Brain
Brain
Nerve
cords
Ventral
nerve
cord
Transverse
nerve
Segmental
ganglia
Figure 49.2c,d Nervous system organization
(c) Planarian (flatworm)
(d) Leech (annelid)

12. (e) Insect (arthropod) (f) Chiton (mollusc)
Fig. 49-2c
Brain
Ganglia
Anterior
nerve ring
Ventral
nerve cord
Longitudinal
nerve cords
Segmental
ganglia
Figure 49.2e, f Nervous system organization
(e) Insect (arthropod)
(f) Chiton (mollusc)

13. (h) Salamander (vertebrate)
Fig. 49-2d
Brain
Brain
Spinal
cord
(dorsal
nerve
cord)
Sensory
ganglia
Ganglia
Figure 49.2g, h Nervous system organization
(g) Squid (mollusc)
(h) Salamander (vertebrate)

14. Central nervous system (CNS) Peripheral nervous system (PNS) Brain
Fig. 49-4
Central nervous
system (CNS)
Peripheral nervous
system (PNS)
Brain
Cranial
nerves
Spinal cord
Ganglia
outside
CNS
Spinal
nerves
Figure 49.4 The vertebrate nervous system

15. The vertebrate brain is regionally specialized :
All vertebrate brains develop from three embryonic regions: forebrain, midbrain, and hindbrain

16. 1. Forebrain includes: Cerebrum
contains the most sophisticated integrating centers
Diencephalon develops into three regions:
epithalamus includes the pineal gland and generates cerebrospinal fluid from blood
thalamus - main input center for sensory information and main output center for motor information
hypothalamus regulates homeostasis and basic survival behaviors such as feeding, fighting, fleeing, and reproducing; circadian rhythms

17. 2. Midbrain:
midbrain contains centers for receipt and integration of sensory information
brainstem - coordinates and conducts information between brain centers

18. 3. Hindbrain includes: Cerebellum controls movement and balance
The pons regulates breathing centers in the medulla
The medulla oblongata contains centers that control several functions including breathing, cardiovascular activity, swallowing, vomiting, and digestion
Cerebellum controls movement and balance

19. Cerebrum (includes cerebral cortex, white matter, basal nuclei)
Fig. 49-9c
Cerebrum (includes cerebral cortex, white matter,
basal nuclei)
Diencephalon (thalamus, hypothalamus, epithalamus)
Midbrain (part of brainstem)
Pons (part of brainstem), cerebellum
Medulla oblongata (part of brainstem)
Cerebrum
Diencephalon:
Hypothalamus
Thalamus
Pineal gland
(part of epithalamus)
Figure 49.9 Development of the human brain
Brainstem:
Midbrain
Pons
Pituitary
gland
Medulla
oblongata
Spinal cord
Cerebellum
Central canal
(c) Adult