Exploring the Somatic Nervous System

Dr. Ketchum's lecture focuses on the efferent division of the peripheral nervous system, particularly the somatic nervous system. The lecture explains the concept of innervation, emphasizing the role of motor neurons in controlling skeletal muscles. It covers the structure and function of motor units and neuromuscular junctions, highlighting the role of acetylcholine as a neurotransmitter. The lecture also distinguishes between nicotinic and muscarinic cholinergic receptors, explaining their responses and the involvement of G proteins.

What does it mean when a nerve innervates an organ?

• The nerve is only connected to the brain.

• The nerve is disconnected from the organ.

• The nerve is connected to the organ and sends signals to or from it.

• The organ sends signals to other organs.

Which type of effector does the somatic nervous system control?

• Glands

• Skeletal muscle

• Smooth muscle

• Cardiac muscle

What is the specific name given to the efferent neuron that innervates skeletal muscle?

• Motor neuron

• Autonomic neuron

• Sensory neuron

• Interneuron

What is another term for a muscle cell?

• Myofibril

• Tendon

• Muscle fiber

• Sarcomere

What does a motor unit consist of?

• A group of motor neurons

• A muscle fiber and all the motor neurons it innervates

• A group of muscle fibers

• A motor neuron and all the muscle fibers it innervates

What is a neuromuscular junction?

• A junction between two muscle fibers

• A junction between a motor neuron and a muscle fiber

• A junction between two motor neurons

• A junction between a sensory neuron and a muscle fiber

What neurotransmitter is found in the synaptic vesicles at the neuromuscular junction?

• Serotonin

• Dopamine

• Acetylcholine

• Norepinephrine

What type of receptors are found on the motor end plate?

• GABA receptors

• Muscarinic cholinergic receptors

• Nicotinic cholinergic receptors

• Adrenergic receptors

Which type of cholinergic receptor generates a fast response when acetylcholine binds to it?

• Muscarinic cholinergic receptors

• Nicotinic cholinergic receptors

• Adrenergic receptors

• GABA receptors

What is required for a slow response when acetylcholine binds to muscarinic cholinergic receptors?

• A second messenger

• A voltage-gated channel

• A G protein

• A ligand-gated channel