Lecture AP Biology Chapter 48 and 49 Nervous systems

After studying this chapter you will be able to understand: The anatomy of a neuron; the mechanisms of impulse transmission in a neuron; the process that leads to release of neurotransmitters, and what happens at the synapse; how the vertebrate brain integrates information, which leads to an appropriate response; different regions of the brain have different functions.

1 Contrast the functions of B cells and T

cells.

2 What are memory cells?

3 How do vaccines work?

4 How does HIV affect the immune

system?

1 Draw and label the parts of a

neuron.

2 Describe saltatory conduction.

3 Explain how a nerve impulse is

transmitted across a neuron.

1. What happens at the synapse?

2. Choose 1 neurotransmitter

Describe its action.

3. What is the role of the following

structures in the human brain?

a) Brainstem

b) Cerebellum

c) Cerebrum

d) Corpus callosum

Chapters 48 & 49

Campbell Biology – 9th ed.

 The anatomy of a neuron.

 The mechanisms of impulse

 Central nervous system (CNS) = brain +

spinal cord

 Peripheral nervous system (PNS) = nerves throughout body

 Sensory receptors: collect info

 Sensory neurons: body  CNS

 Motor neurons: CNS  body (muscles, glands)

 Interneurons: connect sensory & motor

neurons

 Nerves = bundles of neurons

 Contains motor neurons +/or sensory neurons

Peripheral nervous system

Somatic

nervous

system

Autonomic nervous system

Sympathetic division

Parasympathetic division division Enteric

 cell body: contains nucleus & organelles

 dendrites: receive incoming messages

 axons: transmit messages away to other cells

 myelin sheath: fatty insulation covering

axon, speeds up nerve impulses

 synapse: junction between 2 neurons

 neurotransmitter: chemical messengers

sent across synapse

 Glia: cells that support neurons

 Eg Schwann cells (forms myelin sheath)

Reference

electrode

Voltage recorder –70 mV

The Na+/K+ pump (using ATP) maintains

a negative potential inside the neuron.

 Resting potential: membrane potential at rest; polarized

 Na + outside, K + inside cell

 Voltage-gated Na + channel = CLOSED

 Nerve impulse: stimulus stimulus causes a change in membrane potential

 Action potential: neuron membrane depolarizes

 All-or-nothing response

Na + channels

open Na + enters cell

K + channels open K + leaves cell

Saltatory conduction speed: 120 m/sec

 Chemicals released from vesicles by exocytosis into

synaptic cleft

 Diffuse across synapse

 Bind to receptors on neurons, muscle cells, or gland cells

 Broken down by enzymes or taken back up into

surrounding cells

 Types of neurotransmitters:

 Excitatory: speed up impulses by causing

depolarization of postsynaptic membrane

 Inhibitory: slow impulses by causing

hyperpolarization of postsynaptic membrane

 Acetylcholine (ACh): stimulates muscles, memory formation, learning

 Epinephrine: (adrenaline) fight-or-flight

 Norepinephrine: fight-or-flight

 Dopamine: reward, pleasure (“high”)

 Loss of dopamine  Parkinson’s Disease

 Serotonin: well-being, happiness

 Low levels  Depression

 GABA: inhibitory NT

 Affected by alcohol

 Simple, automatic response to a stimulus

 Conscious thought not required

Major Regions: forebrain, midbrain, hindbrain

• Forebrain  cerebrum

• Midbrain  brainstem

cerebellum

•Right & Left cerebral hemispheres

•Corpus callosum: connect

hemispheres

Brainste

m

*Oldest evolutionary part*

•Basic, autonomic survival behaviors

•Medulla oblongata –breathing, heart

& blood vessel activity, digestion, swallowing, vomiting

•Transfer info between PNS & CNS

Cerebellu

m

•Coordinate movement & balance

•Motor skill learning

•Right & Left cerebral hemispheres

hemispheres

Brainste

m

*Oldest evolutionary part*

•Basic, autonomic survival behaviors

•Medulla oblongata –breathing, heart

& blood vessel activity, digestion, swallowing, vomiting

•Transfer info between PNS & CNS

Cerebellu

m

•Coordinate movement & balance

•Motor skill learning

Human Brain

•Right & Left cerebral hemispheres

hemispheres

Brainste

m

*Oldest evolutionary part*

•Basic, autonomic survival behaviors

& blood vessel activity, digestion, swallowing, vomiting

•Transfer info between PNS & CNS

Cerebellu

m

•Coordinate movement & balance

•Motor skill learning

Human Brain

•Right & Left cerebral hemispheres

hemispheres

Brainste

m

*Oldest evolutionary part*

•Basic, autonomic survival behaviors

& blood vessel activity, digestion, swallowing, vomiting

•Transfer info between PNS & CNS

Cerebellu

m

•Coordinate movement & balance

•Motor skill learning

Human Brain