Neurobiology Quiz on Synapses and Nervous System

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Questions and Answers

Which structures are MOST directly involved in long-distance nerve impulse propagation?

Unmyelinated fibers and nerves

Ganglia and gray matter

Cell bodies and ganglia

Nerves and white matter (correct)

What is the PRIMARY distinction between gray matter and white matter in the central nervous system?

Gray matter is involved in motor control; white matter is involved in sensory processing.

Gray matter is unmyelinated; white matter is myelinated. (correct)

Gray matter is myelinated; white matter is unmyelinated.

Gray matter is composed of nerve fibers; white matter contains neuronal cell bodies.

Within the peripheral nervous system, what is the MAIN function of ganglia?

To transmit efferent signals directly to the brain.

To house collections of nerve cell bodies. (correct)

To provide structural support to nerve fibers.

To carry only sensory information.

Which division of the peripheral nervous system is responsible for carrying BOTH sensory and motor information?

The somatic system (C) Signup and view all the answers

Which of the following best describes the relationship between afferent and efferent signals?

Afferent signals travel from the body to the brain, while efferent signals travel from the brain to the body. (C) Signup and view all the answers

What is the primary function of effector nerves in the peripheral nervous system?

To transmit motor information to the periphery. (C) Signup and view all the answers

Which system primarily controls voluntary actions?

The somatic nervous system. (D) Signup and view all the answers

Which division of the autonomic nervous system is associated with the 'fight-or-flight' response?

The sympathetic nervous system. (B) Signup and view all the answers

What is a primary function of the parasympathetic nervous system?

To promote rest and digestive functions. (D) Signup and view all the answers

How does the hypothalamus connect the nervous and endocrine systems?

Through the autonomic nervous system and the pituitary gland. (A) Signup and view all the answers

What is the primary function of the brain-blood barrier?

To regulate the passage of nutrients and protect the brain from harmful substances. (D) Signup and view all the answers

Which of the following best describes the typical flow of information with reference to the terms `pre-synaptic` and `post-synaptic`?

Information flows from pre-synaptic neurons to post-synaptic neurons through electrochemical signals. (A) Signup and view all the answers

What is the role of $Ca^{2+}$ ions in the context of the synapse?

To facilitate the release of neurotransmitters from the pre-synaptic terminal. (D) Signup and view all the answers

What is the anatomical relationship between the central nervous system (CNS) and the peripheral nervous system (PNS)?

The CNS is the control center, and the PNS acts to connect it to the rest of the body. (A) Signup and view all the answers

According to the diagram, what membrane voltage is needed to initiate an action potential in the post synaptic neuron?

-55mV (A) Signup and view all the answers

Which part of the brain is primarily responsible for relaying sensory information to the appropriate areas of the cortex?

Thalamus (D) Signup and view all the answers

The cerebral cortex is primarily composed of which type of matter?

Gray matter with unmyelinated axons (C) Signup and view all the answers

Which of these brain structures is NOT part of the diencephalon?

Cerebellum (C) Signup and view all the answers

What is the main function of the medulla oblongata?

Regulates heart rate, breathing, and blood pressure (A) Signup and view all the answers

Which brain structure is MOST directly involved in the balance needed for smooth coordinated movement?

Cerebellum (B) Signup and view all the answers

What is the main function of the hippocampus within the limbic system?

Processing memory (B) Signup and view all the answers

The longitudinal fissure divides the cerebrum into which two parts?

Left and right hemispheres (C) Signup and view all the answers

Which of the following is primarily responsible for the release of adrenaline in response to fear or anger?

Amygdala (B) Signup and view all the answers

What connects the two cerebral hemispheres?

Corpus callosum (D) Signup and view all the answers

Which of the following is a component of the brain stem?

Pons (B) Signup and view all the answers

What is the specific name for the membranes that support and protect the brain and spinal cord?

Meninges (C) Signup and view all the answers

The ventral root of a spinal nerve is primarily composed of what type of fibers?

Motor fibers leaving the gray matter (D) Signup and view all the answers

Which of these is a function of the hypothalamus?

Regulating body temperature and water balance (B) Signup and view all the answers

What is the function of the pons?

Controlling relaxation reflexes including the urination process (B) Signup and view all the answers

Where are ganglia located?

Groupings of cell bodies outside the Central Nervous System (C) Signup and view all the answers

Study Notes

Electrochemical Synapse

Nerve impulse (action potential) reaches the axon terminal.
Calcium (Ca2+) gated channels open in response to the action potential.
Influx of Ca2+ causes synaptic vesicles containing neurotransmitters (NTs) to fuse with the pre-synaptic neuronal membrane.
NTs release into the synaptic cleft.
NTs bind to sodium channels (Na+) on the post-synaptic membrane.
Opening of Na+ channels causes Na+ to flow into the postsynaptic neuron.
If enough Na+ flows to cross the threshold barrier of -55mV, then an action potential occurs at the end of the postsynaptic neuron.

The Nervous System

Two anatomical divisions: Central Nervous System (CNS) and Peripheral Nervous System (PNS).
Neurons are supported by neuroglial cells in both divisions.

Neuroglial Cells

Supporting nervous system components are microglial (phagocytosis, immunity), oligodendrocytes (myelin), ependymal (CSF), astrocytes (nutrients, growth & protection, blood-brain barrier).
Schwann cells (myelin) are in the PNS.
Satellite cells support cell bodies in the PNS.

Myelin Sheath

Myelin sheath covers some axons, acting as an insulator.
Nodes of Ranvier are gaps in the myelin sheath.
In the peripheral nervous system, myelin is formed by Schwann cells.
In the central nervous system, myelin is formed by oligodendroglial cells.
Nerve regeneration is limited in the CNS.

Nervous System - Part II

The brain is three pounds of fatty tissue covered in a web of blood vessels.

Overview of this Section

Understanding the major regions of the brain.
Knowing the structure and organization of the spinal cord.
Describing the somatic reflex arc and identifying parts of the nervous system involved in the reflex arc.

The Brain

Major regions: Cerebrum, Diencephalon, Cerebellum, Brain Stem.
Other components: Midbrain, Pons, Medulla Oblongata, Thalamus, Hypothalamus, Pituitary Gland, Pineal Gland.

Cerebrum - The Most Superficial Part of the Brain

Two cerebral hemispheres divided by a longitudinal fissure.

Corpus Callosum

Connects the two cerebral hemispheres.

Gray and White Matter in Brain vs. Spinal Cord

Gray matter is unmyelinated; white matter is myelinated.

Peripheral Nervous System

Composed of nerves (bundles of nerve fibers) and ganglia (collections of nerve cell bodies).

Divisions of the Peripheral Nervous System

Somatic system (controls skeletal muscles, voluntary movements).
Autonomic system (controls involuntary processes like cardiac muscles, smooth muscles, and glands - sympathetic and parasympathetic nervous systems).

Somatic System

Responsible for sensory and motor information.
Sensory information is carried from sensory receptors to the CNS.
Motor information is carried to effectors for a response from the CNS.

Autonomic System

Regulates the activity of cardiac muscle, smooth muscle, and glands.
Two divisions: sympathetic and parasympathetic.
Features in common: function automatically and involuntarily, and innervate all internal organs.

Sympathetic division

Mediates the "fight or flight" response.
Increases heart rate, dilates bronchi, and inhibits digestion.

Parasympathetic Division

Mediates the "rest and digest" response
Decreases heart rate, promotes digestion

Hypothalamus

Connects the nervous system and the endocrine system.
Manufactures hormones that control the pituitary gland

Cerebellum

Receives sensory and motor input.
Assures smooth, coordinated movements.

The Limbic System

Amygdala (fight/flight/fawn): responds to anger, fear, defensiveness, and avoidance. Releases adrenaline.
Hippocampus: communicates with the prefrontal cortex and supports memory.

Brain Stem

Midbrain: acts as a relay center between cerebrum and cerebellum; controls reflexes.
Pons: controls relaxation reflexes, including urination.
Medulla oblongata: Controls heart rate, breathing, blood pressure swallowing, coughing, and vomiting.

Spinal Cord

Extends from the base of the brain into the vertebral canal.
Protected by vertebrae and intervertebral disks.
Cross-sectional anatomy; a shaped like letter "H."
Contains dorsal and ventral roots.
Spinal nerves are part of the PNS.

Ganglia

Collection of nerve cell bodies.

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Description

Test your understanding of electrochemical synapses and the structure of the nervous system. This quiz covers the role of neurotransmitters, synaptic transmission, and the support functions of neuroglial cells. Ideal for those studying neurobiology and neuroscience.