Nervous System and Neurons Overview

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Questions and Answers

What is one characteristic of nerve impulse transmission compared to hormone transmission?

It is more widespread.

It targets specific parts of the body. (correct)

Transmission is usually slower.

Effects are long lasting.

What happens when the generator potential in a sensory neurone reaches the threshold level?

An all-or-nothing action potential is triggered. (correct)

An increased frequency of action potentials is generated.

The sensory neurone becomes adapted to the stimulus.

The chemical transmitter is released into the synapse.

Why is the ability to respond to stimuli important for an organism's survival?

It increases the chances of survival against environmental extremes. (correct)

It ensures the development of complex nervous systems.

It allows for better communication with other organisms.

It guarantees a permanent and irreversible effect.

Which of the following is NOT a feature of the endocrine system?

Communication through nerve impulses. (C) Signup and view all the answers

What is the primary function of adaptation in sensory neurones?

To decrease the frequency of action potentials in response to a steady stimulus. (B) Signup and view all the answers

In relation to response duration, how do the nervous and endocrine systems differ?

Nervous system responses are short lived and reversible. (C) Signup and view all the answers

How do rods differ from cones in terms of visual acuity?

Rods share sensory neurones, leading to lower visual acuity. (A) Signup and view all the answers

What role do receptors play in the nervous system?

They detect stimuli to provoke responses. (B) Signup and view all the answers

Which component of rod cells is crucial for the process of light transduction?

Rhodopsin (B) Signup and view all the answers

What type of response does a sensory neurone exhibit if the generator potential is below the threshold level?

No action potential occurs. (C) Signup and view all the answers

What is the primary function of the myelin sheath surrounding axons?

To protect and insulate the axon, speeding up impulse transmission (A) Signup and view all the answers

Which part of the neurone carries nerve impulses towards the cell body?

Dendrite (C) Signup and view all the answers

What distinguishes myelinated neurones from unmyelinated neurones?

Myelinated neurones are covered by Schwann cells and transmit impulses faster (B) Signup and view all the answers

Which type of neurone is responsible for transmitting impulses from a receptor to a relay neurone?

Sensory neurone (C) Signup and view all the answers

What is the role of Schwann cells?

To protect and insulate axons and aid nerve regeneration (A) Signup and view all the answers

Which characteristic is true of motor neurones?

They have one long axon and many short dendrites (A) Signup and view all the answers

What are the gaps between the myelin sheaths called?

Nodes of Ranvier (C) Signup and view all the answers

What role do chemoreceptor cells in taste buds primarily serve?

Converting chemical energy into electrical potential (B) Signup and view all the answers

Which type of stimulus are chemoreceptor cells specifically sensitive to?

Dissolved chemicals (B) Signup and view all the answers

What is the functional significance of the microvilli in chemoreceptor cells?

They provide a large surface area for chemical contact (B) Signup and view all the answers

How do chemoreceptor cells initiate a nerve impulse?

By undergoing a chemical change upon stimulation (B) Signup and view all the answers

Which of the following statements is true regarding the specificity of chemoreceptor cells?

They are specific to a type of dissolved chemical (A) Signup and view all the answers

What is the primary result of the receptor potential generated by chemoreceptor cells?

Releasing a chemical transmitter to a sensory neurone (D) Signup and view all the answers

How many types of basic tastes are recognized by chemoreceptor cells?

Five (A) Signup and view all the answers

Which part of the taste bud allows chemicals from saliva to contact chemoreceptor cells?

Taste pore (B) Signup and view all the answers

What function does the central nervous system perform in relation to sensory receptor feedback?

Perceive and interpret information from receptors (C) Signup and view all the answers

What occurs after a chemical binds to a chemoreceptor cell's specific membrane receptor?

A receptor potential is generated (B) Signup and view all the answers

Study Notes

Nervous Communication and Neurons

The nervous system coordinates homeostatic mechanisms, responding to internal and external environmental changes.
The nervous system and endocrine system are compared as communication systems.
Neurons are specialized cells that rapidly transmit electrochemical signals (nerve impulses).
A neuron has a cell body, dendrites (receiving end), and an axon (transmitting end).
Sensory neurons transmit impulses from receptors to the central nervous system.
Motor neurons transmit impulses from the central nervous system to effectors (muscles or glands).
Relay neurons (interneurons) transmit impulses between other neurons.
Myelinated neurons conduct impulses faster than unmyelinated neurons.
Myelin sheaths are formed by Schwann cells wrapped around axons.
Nodes of Ranvier are gaps in the myelin sheath.
The central nervous system consists of the brain and spinal cord.

Stimulus and Response

Organisms respond to internal or external stimuli.
Responses increase the chances of survival.
Receptors detect stimuli.
Effectors carry out responses.

Comparison of Nervous and Endocrine Systems

Endocrine system uses hormones transmitted through the blood, transmission is slow, effects are widespread, and responses are slow but long-lasting often permanent
Nervous system uses nerve impulses transmitted through nerve fibers, transmission is rapid, effects are localized (specific), and responses are rapid but short-lived, and temporary.

Structure of Neurons

Neurones have a cell body containing a nucleus; mitochondria, and rough endoplasmic reticulum (Nissl's granules).
Dendrons (branching extensions) conduct impulses towards the cell body.
The axon transmits impulses away from the cell body.
Axons can be myelinated or unmyelinated with myelin providing insulation and speeding signal transmission.

Sensory Receptors

Sensory receptors detect stimuli and are often located in sensory organs.
Chemoreceptors in taste buds detect dissolved chemicals.
Taste buds are located on the tongue's epithelium.
Each bud has 50-100 chemoreceptors with microvilli for maximal surface area.
Chemoreceptors convert stimulus energy into a receptor potential.
Receptor potentials lead to generator potentials in sensory neurons and can trigger action potentials.
Adaptation in receptors is a slow decline in response to a continuous stimulus.
Sensory receptors are specific to stimuli and act as transducers converting stimulus energy into receptor potential.

Rods and Cones as Light Receptors

Rods and cones are photoreceptor cells in the retina.
Rods are more numerous than cones and are sensitive to light but not color.
Cones are less sensitive to light but distinguish different colors.
Transduction in light receptor cells occurs via rhodopsin (rods) or iodopsin (cones), which change form when exposed to light.
The change in shape leads to a chain of reactions that change the permeability of the membrane of the receptor cell, creating a generator potential if the threshold is exceeded.

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Description

Explore the functions and components of the nervous system in this quiz. Discover how neurons communicate and the roles of sensory, motor, and relay neurons. Test your knowledge on the structure of neurons and the importance of myelin sheaths in impulse transmission.