Presentation on theme: "Study guide…part 1 What are the three types of neurons? What is the structure of a neuron? How does saltatory conduction change the speed of the impulse?"— Presentation transcript:
Study guide…part 1 What are the three types of neurons? What is the structure of a neuron? How does saltatory conduction change the speed of the impulse? Explain the resting and action potential as they relate to a nerve impulse. How does the nerve impulse travel across the synapse?
Types of neurons and neuron structure 3 types of neurons: Sensory Interneurons Motor Neuron structure: Cell body Dendrite Axon Nodes of Ranvier
The myelin sheath A lipid covering on long axons How does it affect the speed of the impulse? Saltatory conduction – conduction of the nerve impulse from node to node Let me inflict some pain… What disease results when the immune system attacks this myelin sheath?
The nerve impulse: Set up the resting potential Resting potential – when the axon is not conducting a nerve impulse More positive ions outside than inside the membrane -65mV inside the axon – Where is Na+ concentrated? – Where is K+ concentrated?
Depolarization A sodium channel opened? – What direction would they move based on their concentration? – What direction would they move based on their charge? – How would the charge inside the cell change?
Repolarization A potassium channel opened? – What direction would they move based on their concentration? – What direction would they move based on their charge? – How would the charge inside the cell change?
The nerve impulse: action potential Action potential – rapid change in the axon membrane that allows a nerve impulse to occur Sodium gates open letting Na + in Depolarization occurs Potassium gates open letting K + out Repolarization occurs Wave of depolarization/repolarization travels down the axon How is the resting potential restored?
The synapse A small gap between the sending neuron (presynaptic membrane) and the receiving neuron (postsynaptic membrane) Transmission is accomplished across this gap by a neurotransmitter What neurotransmitters do you already know? Where are neurotransmitters stored?
How does transmission across the synapse occur? Nerve impulse reaches the axon terminal _________________enter the axon terminal that stimulate the synaptic vesicles to fuse with the presynaptic membrane – What is the name of this process of exiting the cell? Neurotransmitters diffuse across the synapse and bind with the postsynaptic membrane to inhibit or excite the neuron
Study guide…part 2 What are the two parts of the nervous system? What protects the CNS? Be able to explain the parts of the brain and their functions. How is the nervous system organized into the divisions? Contrast the functions of the sympathetic and parasympathetic divisions. Describe Alzheimers and Parkinsons.
The nervous divisions 2 divisions: – Central nervous system (CNS): Brain and spinal cord – Peripheral nervous system (PNS): Nerves and ganglia (cell bodies)
The central nervous system Consists of the brain and spinal cord Both are protected by: Bones – Meninges – 3 protective membranes that wrap around CNS Cerebral spinal fluid (CSF) –
The CNS: Spinal cord Extends from the base of the brain and along the length of the vertebral canal Functions to provide communication between the brain and most of the body Can the spinal cord make decisions?
Diencephalon Includes the: Hypothalamus- Thalamus- Pineal gland-
Cerebellum Receives and integrates sensory input from the eyes, ears, joints and muscles about the current position of the body Functions to: Maintains posture Coordinates voluntary movement Allows learning of new motor skills (i.e. playing the piano or hitting a baseball)
The brain stem Includes: Midbrain- Pons- Medulla oblongata-
The limbic system Joins primitive emotions (i.e. fear, pleasure) with higher functions such as reasoning Can cause strong emotional reactions to situations but conscious thought can override and direct our behavior Includes: Amygdala- Hippocampus-
The peripheral nervous system (PNS) Includes cranial (12 pr) and spinal nerves (31 pr) and ganglia outside the CNS - Spinal nerves conduct impulses to and from the spinal cord - Cranial nerves conduct impulses to and from the brain Divided into 3 systems: - Somatic - Autonomic - Enteric
The PNS: Somatic division Serves the skin, skeletal muscles and tendons
The PNS: Autonomic division Regulates the activity of involuntary muscles (cardiac and smooth) and glands Divided into 2 divisions: – Sympathetic – Parasympathetic What about enteric?
Health focus: Degenerative brain disorders Alzheimer disease – Usually seen in people after 65 yrs. old – Starts with memory loss – Abnormal neurons with plaques of beta amyloid proteins – What causes the plaques? Parkinson disease – Usually begins between the ages of 50-60 – Characterized by loss of motor control – Due to degeneration of _____________-releasing neurons in the brain