Nervous System

What are the two main components of the nervous system?

The central nervous system (CNS) and the peripheral nervous system (PNS).

What does the central nervous system (CNS) comprise?

The brain and spinal cord.

What does the peripheral nervous system (PNS) comprise?

Cranial nerves and spinal nerves.

What is the primary role of sensory nerves?

To transmit various types of sensory information like touch, light, and temperature.

How do motor nerves function within the nervous system?

They control voluntary muscle contractions through the somatic nervous system and involuntary functions through the autonomic nervous system.

What does the autonomic nervous system control?

Involuntary functions such as heart rate, smooth muscle contraction, and glandular secretions.

What are the two branches of the autonomic nervous system?

The sympathetic nervous system and the parasympathetic nervous system.

What does the sympathetic nervous system control?

The 'fight-or-flight' responses.

What does the parasympathetic nervous system control?

'Rest and repose' functions, maintaining normal physiological levels.

What are the main differences between the somatic and autonomic nervous systems?

Somatic is voluntary and controls skeletal muscle contraction; autonomic is involuntary and controls internal organs and glands.

What is a nerve?

A bundle of nerve cells or nerve fibers.

What is the basic cellular unit of the nervous system?

A nerve cell, also known as a neuron.

What are the main parts of a neuron?

Cell body, dendrites, axon, and myelin sheath.

What is the function of dendrites?

They pick up stimuli and channel an impulse toward the nerve cell body.

What role does the axon play in a neuron?

It carries the impulse away from the nerve cell body.

What is the myelin sheath?

A fatty material that insulates some axons, facilitating faster impulse transmission.

What are nodes of Ranvier?

Gaps in the myelin sheath where the axon membrane is exposed, critical for speeding up impulse transmission.

What are neurotransmitters?

Chemicals produced by nerve cells that transmit signals across the synapse.

What is the space between nerve cells called?

A synapse.

What is the role of Schwann cells?

To support the nervous system and secrete the myelin sheath.

What is the function of the sodium-potassium pump?

To establish concentration and charge gradients across the nerve cell membrane.

What creates the resting membrane potential of a nerve cell?

A difference in ion concentrations inside and outside the cell, primarily maintained by the sodium-potassium pump.

What is depolarization in terms of a nerve impulse?

The phase where the inside of the neuron becomes positively charged due to the influx of sodium ions.

What happens during repolarization?

Potassium ions rush out of the cell, restoring the resting membrane potential.

How does a nerve impulse propagate along the axon?

Through a continuous cycle of depolarization and repolarization, opening sodium channels in adjacent areas.

What is the role of calcium ions in neurotransmitter release?

Calcium ions stimulate vesicles to fuse with the axon membrane and release neurotransmitters into the synapse.

What is GABA and what role does it play?

An inhibitory neurotransmitter that reduces the likelihood of nerve cell firing.

What is acetylcholine's key function in the nervous system?

To initiate muscle contraction at neuromuscular junctions.

What functions are associated with dopamine?

Sensations of pleasure, feeling reward, and motivation to carry out behaviors.

What is the limbic system responsible for?

Emotions, memory processing, and control of emotional responses.

What did Phineas Gage's accident reveal about the brain?

Different areas of the brain control different functions, particularly involving emotions and personality.

What part of the brain is the thalamus associated with?

The central relay station for almost all sensory information.

What role does the hypothalamus play in the body?

Regulating thirst, hunger, emotions, and homeostasis.

What is the primary role of the cerebellum?

Coordinating complex muscle movements and maintaining posture and balance.

What are the three main regions of the brain?

Cerebrum, cerebellum, and medulla (and brainstem).

What are the functional areas of the cerebrum responsible for?

Speech, interpreting auditory and visual information, and complex thought.

What is the role of the corpus callosum?

To connect the left and right cerebral hemispheres, allowing communication between them.

How do the sympathetic and parasympathetic nervous systems differ in nerve origin?

Sympathetic originates from the thoracic and lumbar spinal nerves; parasympathetic originates from cranial and sacral spinal nerves.

What neurotransmitter is primarily secreted by the parasympathetic nervous system?

Acetylcholine (ACh).

What is the significance of cerebral lateralization?

Different functions are preferentially associated with either the left or right hemisphere of the brain.

How does the primary motor cortex function?

It initiates planned actions for voluntary movements.

What happens at the synapse when neurotransmitters are released?

They diffuse to the postsynaptic membrane and bind to receptors to propagate the signal.

What are the characteristics of the left cerebral hemisphere?

Associated with mathematical tasks, logical thinking, and stepwise sequencing.

What defines the right cerebral hemisphere's specialization?

Interpreting shapes, colors, and creative tasks.

What is the resting membrane potential approximately?

-70 millivolts.

What physical changes occur in a neuron during action potential?

Changes in ion concentrations lead to depolarization and repolarization.

What are the effects of cutting connections in the nervous system?

Deterioration of function and capability of the nervous system to relay impulses.

How does the body maintain homeostasis through the autonomic nervous system?

By regulating involuntary life processes like heart rate, digestion, and respiratory functions.

Describe a reflex arc's pathway. What are the main components involved?

Sensory receptor → Sensory neuron → Association neuron → Motor neuron → Effector.

Why is the medulla considered the life support system of the brain?

It controls essential functions like respiration, circulation, and digestion.

What role do neurotransmitters like nitric oxide play in the nervous system?

They function as signaling molecules that can diffuse between cells and have diverse physiological effects.

How does the primary auditory cortex differ from the auditory association area?

The primary auditory cortex processes basic aspects of sound, while the association area integrates and recognizes sounds.

What is the main function of the visual cortex?

To receive and analyze visual information from the thalamus.

What critical function does the reticular activating system serve?

Maintaining consciousness and regulating sleep-wake cycles.

What physiological response does the sympathetic nervous system trigger?

Fight or flight response.

What is the primary hormone produced by the hypothalamus related to water regulation?

Antidiuretic hormone (ADH).

What is the function of the medulla oblongata in the nervous system?

Regulates involuntary functions necessary for survival, such as heart rate and breathing.

How does a typical synapse operate?

Neurotransmitters are released from the presynaptic neuron into the synaptic cleft and bind to receptors on the postsynaptic neuron.

What distinguishes a motor neuron from a sensory neuron?

Motor neurons carry impulses away from the central nervous system to effector organs, while sensory neurons carry impulses toward the CNS.

What is a primary concept associated with 'neuromuscular junctions'?

The site where motor neurons connect with the muscle fibers to initiate contraction.

How do inhibitory neurotransmitters like GABA affect nerve cell activity?

They make it less likely for the next nerve cell to fire.

What is the effect of the sodium-potassium pump on the neuron's resting state?

It creates a negative internal environment relative to the outside, crucial for generating an action potential.

What neurotransmitter is involved in the regulation of mood and sleep?

Serotonin.

What effect do pathological disorders with myelin sheaths have on nerve function?

They impede impulse conduction, leading to neurological deficits.

What impact does the cerebellum have on motor control?

It is essential for balance, posture, and smoothing out complex movements.

What is the role of the Association Neuron (Interneuron) in a reflex arc?

To connect sensory neurons and motor neurons within the spinal cord.

What type of neurotransmitter is epinephrine, and what is its primary function?

A neurotransmitter and hormone that plays a key role in the fight-or-flight response.

How do sensory neurons connect to the spinal cord?

They carry information from sensory receptors to the spinal cord.

Why are the meninges important for brain protection?

They provide a protective membrane around the brain.

What is a key function of the limbic system?

It is involved in the processing and regulation of emotions.

What does the terms ‘premotor cortex’ and ‘primary motor cortex’ refer to?

Areas in the frontal lobe that plan movements and initiate motor actions, respectively.