Biology Chapter on Nervous System Functions

Questions and Answers

What is a primary function of the nervous system in relatively primitive species?

Maintenance of the internal environment (correct)

Learning and memory enhancement

Advanced cognitive processing

Facilitating complex social interactions

As the evolutionary scale ascends, what is an increasing capability of the nervous system?

Greater reliance on instinctual responses

Less functionality related to homeostasis

Simplified communication skills

Increased ability for cognitive functions (correct)

What underpins the importance of neuroanatomical knowledge in clinical practices?

Nutritional deficiencies affecting the nervous system

Understanding structural changes associated with neurological disorders (correct)

The simplicity of neurological structures

Maximizing muscle response and strength

Which aspect of the nervous system is considered most developed in humans?

Complexity and versatility Signup and view all the answers

What is homeostasis in the context of the nervous system?

The maintenance of stable internal conditions Signup and view all the answers

What fields of research are still ongoing regarding the nervous system?

Anatomical and physiological explanations of neural function Signup and view all the answers

What terminology standard governs the naming of parts within the nervous system?

Terminologia Anatomica Signup and view all the answers

Which of the following factors can lead to damage in the nervous system?

Inherited and developmental abnormalities Signup and view all the answers

What term is used to describe the position towards the tail end in embryology?

Caudal Signup and view all the answers

In neuroanatomy, which directional term is used for the back?

Dorsal Signup and view all the answers

Which structure is named after a person for their prominence in describing it?

Foramen of Monro Signup and view all the answers

What common characteristic do all neurones share?

A single cell body with branching processes Signup and view all the answers

Which of the following terms describes a structure position closer to the midline of the body?

Medial Signup and view all the answers

What term is commonly used for the special regions where information passes between neurones?

Synapses Signup and view all the answers

In clinical neuroradiology, how are axial images typically oriented?

Looking from the subject's feet towards the head Signup and view all the answers

Which plane is known as the transverse plane in radiology?

Axial Signup and view all the answers

What is the estimated number of neurones in the human nervous system?

Approximately 10 billion Signup and view all the answers

Which of the following is NOT a function of a neurone?

Storing genetic information Signup and view all the answers

What structure carries information away from the cell body in a neuron?

Axon Signup and view all the answers

What specialisation occurs at the end of an axon to facilitate information transfer?

Nerve terminals Signup and view all the answers

When a neuron is stimulated above a certain threshold, which event occurs?

Action potential Signup and view all the answers

What type of cell is responsible for the formation of myelin in the central nervous system?

Oligodendrocytes Signup and view all the answers

Which part of the nervous system is primarily responsible for processing information?

Central nervous system Signup and view all the answers

What is the primary role of neurotransmitters in neuron communication?

To facilitate the transmission of information Signup and view all the answers

How does the membrane potential of a neuron behave at rest?

It is approximately 60-70 mV, with the inside being negative Signup and view all the answers

What happens to the membrane potential when a neurotransmitter binds to its receptor?

It can either depolarize or hyperpolarize the membrane Signup and view all the answers

What is the function of neuroglial cells in the nervous system?

Supporting and maintaining neuronal function Signup and view all the answers

What is the role of the peripheral nervous system?

To transmit sensory information to the brain and spinal cord Signup and view all the answers

Which statement accurately describes the somatic nervous system?

It is involved in detecting changes in the external environment. Signup and view all the answers

What is the primary function of efferent neurones?

They carry impulses away from the CNS. Signup and view all the answers

What distinguishes the sympathetic and parasympathetic divisions of the autonomic nervous system?

They generally have opposing effects on their target organs. Signup and view all the answers

What is the term for nerve cell bodies located in the CNS that have similar functions?

Nuclei Signup and view all the answers

What is the process called that led to the significant development of the cerebral hemispheres?

Prosencephalisation Signup and view all the answers

What role did the cerebral hemispheres assume during the process of prosencephalisation?

They took on an executive role in various brain functions. Signup and view all the answers

Which characteristic is true of grey matter in the CNS?

It contains a high density of nerve cell bodies. Signup and view all the answers

How do sensory pathways operate within the CNS?

They cross over to the opposite side of the CNS. Signup and view all the answers

Where is the highest level for the perception and interpretation of sensory input localized?

Cortex of the cerebral hemispheres Signup and view all the answers

Which part of the brain developed into the cerebellum?

Caudal end Signup and view all the answers

What plays a crucial role in information transfer between neurons?

Synapses Signup and view all the answers

What did the sensory centres for vision and hearing primarily retain in the human brain?

Reflexive functions Signup and view all the answers

Which of the following accurately describes neuroglial cells?

They have roles other than direct information processing. Signup and view all the answers

What is the resting membrane potential of a typical neurone?

-70 mV Signup and view all the answers

What anatomical structure on the dorsal surface of the midbrain relates to the senses?

Corpora quadrigemina Signup and view all the answers

Which sensory function has a reduced proportion of the adult human cerebral hemisphere dedicated to it?

Olfactory function Signup and view all the answers

Which type of neurone is responsible for carrying information to the CNS?

Afferent neurones Signup and view all the answers

How did the development of the cerebral hemispheres influence other integrative centres in the brain?

Other centres became progressively subservient. Signup and view all the answers

What structure is the prosencephalon primarily associated with?

Cerebrum Signup and view all the answers

Which brain vesicle does the myelencephalon develop into?

Medulla oblongata Signup and view all the answers

What condition is characterized by an underdeveloped brain and skull?

Anencephaly Signup and view all the answers

What does the pontine flexure mark in the developing brain?

The junction between the mesencephalon and metencephalon Signup and view all the answers

Which of the following brain structures undergoes the greatest development within the cerebrum?

Telencephalon Signup and view all the answers

What is the relationship between the development of the neural tube and vertebrate evolution?

The neural tube reflects major changes in phylogenetic development. Signup and view all the answers

Which structure is primarily formed from the rhombencephalon?

Myelencephalon Signup and view all the answers

In which embryonic stage can the three primary brain vesicles be identified?

By the fifth week Signup and view all the answers

What part of the central nervous system does the mesencephalon contribute to?

The brainstem Signup and view all the answers

Which term describes the nerve coverings and structures involved in developmental anomalies of the nervous system?

Ectoderm Signup and view all the answers

What is primarily formed from the ectoderm during embryonic development?

Nervous system Signup and view all the answers

Which structure is formed by the fusion of the neural folds?

Neural tube Signup and view all the answers

What predominantly develops from the basal plate of the embryonic spinal cord?

Motor functions Signup and view all the answers

What type of pathways generally decussate in the CNS?

Both ascending sensory and descending motor pathways Signup and view all the answers

During which week of embryonic development does the formation of the neural tube complete?

Fourth week Signup and view all the answers

Which region of the neural tube primarily develops into the brain?

Rostral part Signup and view all the answers

What is the role of the sulcus limitans during the development of the spinal cord?

To delineate alar and basal plate regions Signup and view all the answers

What are the clusters of cell bodies with similar functions in the CNS referred to as?

Nuclei Signup and view all the answers

Which type of neuron receives general sensory input from the periphery?

General somatic afferent Signup and view all the answers

What primarily constitutes the white matter within the CNS?

Nerve fibers Signup and view all the answers

Study Notes

Overview of the Nervous System

Detects changes in both internal and external environments to ensure individual survival and species propagation.
Primitive nervous systems focus on maintaining homeostasis, responding to stimuli, finding food, and mating.

Higher Functions in Evolved Species

Advanced nervous systems exhibit higher functions: learning, memory, cognition, self-awareness, intellect, and personality.
Human nervous system is recognized as the most complex and versatile evolutionary product.

Importance of Neurological Research

Understanding the anatomy and function of the nervous system is critical for diagnosing and treating neurological disorders.
Ongoing research aims to clarify the anatomical, physiological, biochemical, and molecular bases of neural function.

Neuroanatomical Terminology

Anatomical nomenclature is standardized globally by the Federative Committee on Anatomical Terminology.
Many terms derive from Greek or Latin, with some named after contributors to the field (e.g., Circle of Willis, Foramen of Monro).
Locations of structures described with reference to three planes: sagittal, horizontal (axial), and coronal (frontal).

Directions in Neuroanatomy

Specialized terms used: rostral (toward the head), caudal (toward the tail), dorsal (back), ventral (belly).
Brain structure's long axis distorts during development, requiring the reserved usage of specific terms.

Components of the Nervous System

Neurons are the primary structural and functional units, estimated at 10^10 in humans.
Neurons transmit information through action potentials, with synapses facilitating communication via neurotransmitters.

Types of Neurons

Afferent neurons: carry sensory information to the CNS.
Efferent neurons: transmit impulses from the CNS to muscles and glands (motor functions).
Interneurons: primarily connect circuits within the CNS.

Neuroglial Cells

Neuroglia outnumber neurons and support neuronal function but do not process information directly.
Oligodendrocytes produce myelin, enhancing action potential conduction speed.

Central and Peripheral Nervous Systems

CNS includes the brain and spinal cord, protected by the cranium and vertebral column, constituting the core of neural processing.
PNS connects the CNS to the body, comprising cranial and spinal nerves, as well as peripheral ganglia.

Somatic vs. Autonomic Nervous Systems

Somatic nervous system: responsible for movement and external environmental detection.
Autonomic nervous system: regulates internal organ functions and homeostasis, further divided into sympathetic and parasympathetic divisions.

Grey and White Matter

Grey matter: areas rich in neuron cell bodies, located centrally around the spinal cord's central canal.
White matter: primarily contains myelinated fibers or axons, allowing for rapid signal transmission.

Decussation of Pathways

Sensory and motor pathways generally cross at some point, leading to contralateral processing where each hemisphere controls the opposite body's side.

Development of the Central Nervous System

Initiates during the second week of embryonic development from the ectoderm layer (neural formation called neurulation).
Forms the neural tube, which gives rise to the CNS; differentiation leads to the emergence of brain structures.

Brain Vesicle Development

By the fifth week, three primary brain vesicles form: prosencephalon (forebrain), mesencephalon (midbrain), rhombencephalon (hindbrain).
Further differentiation leads to five secondary brain vesicles.

Structure of the Adult Brain

The prosencephalon develops into the cerebrum, consisting of a cerebral cortex (grey matter) and inner white matter with nuclei.
Diencephalon predominantly forms the thalamus, integral for cortex connectivity.
Mesencephalon remains less differentiated during early development phases.### Brain Development
Metencephalon differentiates into the pons and the cerebellum.
Myelencephalon develops into the medulla oblongata, together forming part of the brainstem, which includes the medulla, pons, and midbrain.

Developmental Anomalies

Developmental disorders can disrupt normal growth and structure of the spinal cord and brain.
Anencephaly results in an infant with an underdeveloped brain and skull, often leading to non-survival.
Spina bifida involves underdevelopment of the lower spinal cord, leaving nerve roots exposed, which can result in paralysis, atrophy of lower limbs, and loss of bowel and bladder control.

Evolutionary Context

There are parallels between embryonic brain development and the evolutionary changes from simple to complex organisms.
Early chordates, such as amphioxus, exhibit a dorsal tubular nerve cord that resembles the neural tube in mammalian embryos.
Significant modifications at the rostral end of the nervous system have occurred throughout evolution, resulting in the complex adult human brain.

Regional Specialization

Evolution led to specialization in brain regions associated with senses and movement control, through expansions from the simple tubular brain.
Development of bilateral centers for smell, vision, and hearing, alongside a symmetrical midline center for balance and equilibrium.
The olfactory part of the brain evolved dramatically into the large cerebral hemispheres, a process known as prosencephalization.

Functional Implications of Prosencephalization

The cerebral hemispheres assume executive functions for sensory perception and voluntary motor control, diminishing the role of older integrative centers.
A minimal portion of the cerebral hemispheres is dedicated to olfactory function, highlighting a shift in sensory processing dominance.
Reflexive functions related to vision and hearing are managed by smaller evolutionary remnants (corpora quadrigemina) on the midbrain's surface.

Importance of Cerebellum

The cerebellum, evolving from the caudal brain, is essential for equilibrium maintenance and movement coordination, continuing its role from early development through to adulthood.

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Description

This quiz explores the functions of the nervous system across various animal species, emphasizing the mechanisms of homeostasis and responses to stimuli. It also covers essential behaviors such as finding food and mating, highlighting the evolutionary advancements in nervous systems. Test your understanding of these vital biological concepts!