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Detailed Notes on Nervous System PDF: Anatomy, Functions, and Action Potential

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Detailed Notes on Nervous System PDF: Anatomy, Functions, and Action Potential
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Bianca Stratford

@biancastratford

·

502 Followers

Follow

The nervous system is a complex network that coordinates high-speed responses in the body, working alongside the endocrine system to maintain homeostasis. It consists of neurons, the structural and functional units, which are supported by neuroglia cells. The central nervous system (CNS) and peripheral nervous system (PNS) work together to process information and control bodily functions.

• Neurons have specialized structures including the cell body, dendrites, and axons
• Different types of neurons serve sensory, motor, and interneuron functions
• Action potentials allow rapid signal transmission along neurons
• The brain and spinal cord make up the CNS, protected by meninges and cerebrospinal fluid
• Key brain regions include the cerebrum, cerebellum, and brainstem

Highlight: Understanding neuron structure and function is crucial for grasping how the nervous system operates.

2/11/2023

57

NERVOUS SYSTEM Endocrine System ↓ Slow speed coordination Nervous System + High speed coordination Homeastatic State (tendency of body to re

View

Neuron Structure and Types

Neurons, the fundamental units of the nervous system, have distinct structural components that enable their function. The cell body, or cyton, contains important cellular structures:

  1. Nissl's granules (tigroid body): Involved in protein synthesis
  2. Neurofibrils: Aid in internal conduction

The axon, a key component for signal transmission, can be either myelinated or non-myelinated. Myelinated axons in the central nervous system are covered by oligodendrocytes, while those in the peripheral nervous system are wrapped by Schwann cells.

Neurons can be classified based on their function:

  1. Sensory neurons (receptors)
  2. Motor neurons (effectors)
  3. Interneurons (interconnecting)

Definition: Myelin sheath - A fatty insulating layer around some axons that speeds up signal transmission.

Example: The thyroxine hormone, along with vitamin B12, plays a crucial role in the multiplication and division of neurons during embryonic development.

NERVOUS SYSTEM Endocrine System ↓ Slow speed coordination Nervous System + High speed coordination Homeastatic State (tendency of body to re

View

Action Potential Generation

The action potential is a key process in nervous system physiology, involving several stages:

  1. Polarization (Resting State): The neuron maintains a resting membrane potential of about -70mV.

  2. Depolarization: A stimulus causes sodium channels to open, allowing sodium ions to flow into the cell. This raises the membrane potential to the threshold level (about -55mV).

  3. Rising Phase: If the threshold is reached, more voltage-gated sodium channels open, causing a rapid influx of sodium ions. The membrane potential quickly rises to about +30 to +45mV.

  4. Repolarization: Potassium channels open, and potassium ions flow out of the cell. Simultaneously, sodium channels close. This causes the membrane potential to return towards the resting level.

  5. Hyperpolarization: The membrane potential briefly becomes more negative than the resting state due to the continued outflow of potassium ions.

Vocabulary: Threshold potential - The minimum membrane potential that triggers an action potential.

Highlight: The 7 steps of action potential involve polarization, depolarization, rising phase, peak, falling phase, repolarization, and hyperpolarization.

NERVOUS SYSTEM Endocrine System ↓ Slow speed coordination Nervous System + High speed coordination Homeastatic State (tendency of body to re

View

Brain Structure and Development

The brain develops from the neural tube, which forms five primary vesicles:

  1. Telencephalon (forms the cerebrum)
  2. Diencephalon (forms the thalamus and hypothalamus)
  3. Mesencephalon (forms the midbrain)
  4. Metencephalon (forms the pons and cerebellum)
  5. Myelencephalon (forms the medulla oblongata)

The cerebrum, the largest part of the brain, consists of gray matter (cortex) and white matter. It is divided into several lobes, each with specific functions:

  • Frontal lobe: Motor control, planning, reasoning
  • Parietal lobe: Sensory processing
  • Temporal lobe: Auditory processing, memory
  • Occipital lobe: Visual processing

Example: The Broca's area in the frontal lobe is responsible for speech production, while Wernicke's area in the temporal lobe is involved in language comprehension.

Highlight: Understanding the nervous system anatomy and physiology is crucial for comprehending how different brain regions contribute to various functions.

NERVOUS SYSTEM Endocrine System ↓ Slow speed coordination Nervous System + High speed coordination Homeastatic State (tendency of body to re

View

Factors Affecting Neuron Function

Several factors influence the functioning of neurons in the nervous system. Key among these are:

  1. Na-K pump (Active transport): This protein actively moves sodium and potassium ions across the cell membrane, maintaining the resting potential.

  2. Ion channels (Passive transport): These channel proteins allow specific ions to move across the membrane based on concentration gradients.

  3. Negatively charged proteins and associated anions: These contribute to the overall charge distribution across the neuron membrane.

The brain's functional areas play crucial roles in various processes:

  • Motor areas control movement
  • Sensory areas process incoming sensory information
  • Association areas integrate information and are involved in higher cognitive functions

Highlight: The balance of ions across the neuron membrane is critical for proper nervous system function and signal transmission.

NERVOUS SYSTEM Endocrine System ↓ Slow speed coordination Nervous System + High speed coordination Homeastatic State (tendency of body to re

View

Nervous System Components

The central nervous system (CNS) consists of the brain and spinal cord, which are protected by several layers:

  1. Dura mater: The outermost tough protective layer
  2. Arachnoid mater: The middle layer
  3. Pia mater: The innermost layer, closely adhering to the brain and spinal cord

The brain contains fluid-filled cavities called ventricles:

  1. Two lateral ventricles
  2. Third ventricle
  3. Cerebral aqueduct
  4. Fourth ventricle

Cerebrospinal fluid (CSF) is produced by the choroid plexus and circulates through these ventricles, providing cushioning and nutrients.

Definition: Choroid plexus - A network of blood vessels and cells in the ventricles that produces cerebrospinal fluid.

Highlight: The central nervous system is well-protected by meninges and bathed in cerebrospinal fluid, which provides both physical and chemical protection.

NERVOUS SYSTEM Endocrine System ↓ Slow speed coordination Nervous System + High speed coordination Homeastatic State (tendency of body to re

View

Limbic System and Hypothalamus

The limbic system is a group of interconnected structures involved in emotion, behavior, and memory. Key components include:

  1. Amygdala: Processes emotions, particularly fear and aggression
  2. Hippocampus: Crucial for forming new memories and spatial navigation

The hypothalamus is a small but vital structure that serves as a link between the nervous system and the endocrine system. Its functions include:

  1. Regulating behavior and emotions
  2. Controlling the endocrine system through the pituitary gland
  3. Thermoregulation
  4. Autonomic nervous system control
  5. Maintaining the body's biological clock

The olfactory system, responsible for the sense of smell, consists of:

  1. Olfactory bulbs: Receive input from olfactory receptors in the nose
  2. Olfactory tract: Transmits information to other brain areas
  3. Olfactory cortex: Processes and interprets smell information

Vocabulary: Olfactory - Relating to the sense of smell.

Highlight: The hypothalamus plays a crucial role in maintaining homeostasis by integrating nervous system function with endocrine system control.

NERVOUS SYSTEM Endocrine System ↓ Slow speed coordination Nervous System + High speed coordination Homeastatic State (tendency of body to re

View

Nervous System Overview

The nervous system is a vital component of the body's regulatory mechanisms, working in tandem with the endocrine system to maintain homeostasis. While the endocrine system provides slow-speed coordination, the nervous system offers high-speed coordination, allowing for rapid responses to stimuli.

The basic structural and functional unit of the nervous system is the neuron. Neurons consist of several key parts:

  1. Cyton (cell body or pericaryon): The main regulating part
  2. Dendrites: Processes that receive signals
  3. Axon: The main functional part for transmitting signals

Supporting the neurons are neuroglia cells, which provide essential functions such as packaging, protection, support, and nutrition to the neurons.

Vocabulary: Homeostasis - The tendency of the body to maintain a stable internal environment.

Highlight: The nervous system's ability to provide high-speed coordination is crucial for rapid responses to environmental changes and internal stimuli.

NERVOUS SYSTEM Endocrine System ↓ Slow speed coordination Nervous System + High speed coordination Homeastatic State (tendency of body to re

View

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Subjects

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AP Biology

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Cell structure and function

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Cell regulatory mechanisms like osmosis and selective permeability

/

Osmosis,permeability

Detailed Notes on Nervous System PDF: Anatomy, Functions, and Action Potential

user profile picture

Bianca Stratford

@biancastratford

·

502 Followers

Follow

The nervous system is a complex network that coordinates high-speed responses in the body, working alongside the endocrine system to maintain homeostasis. It consists of neurons, the structural and functional units, which are supported by neuroglia cells. The central nervous system (CNS) and peripheral nervous system (PNS) work together to process information and control bodily functions.

• Neurons have specialized structures including the cell body, dendrites, and axons
• Different types of neurons serve sensory, motor, and interneuron functions
• Action potentials allow rapid signal transmission along neurons
• The brain and spinal cord make up the CNS, protected by meninges and cerebrospinal fluid
• Key brain regions include the cerebrum, cerebellum, and brainstem

Highlight: Understanding neuron structure and function is crucial for grasping how the nervous system operates.

2/11/2023

57

 

AP Biology

2

NERVOUS SYSTEM Endocrine System ↓ Slow speed coordination Nervous System + High speed coordination Homeastatic State (tendency of body to re

Neuron Structure and Types

Neurons, the fundamental units of the nervous system, have distinct structural components that enable their function. The cell body, or cyton, contains important cellular structures:

  1. Nissl's granules (tigroid body): Involved in protein synthesis
  2. Neurofibrils: Aid in internal conduction

The axon, a key component for signal transmission, can be either myelinated or non-myelinated. Myelinated axons in the central nervous system are covered by oligodendrocytes, while those in the peripheral nervous system are wrapped by Schwann cells.

Neurons can be classified based on their function:

  1. Sensory neurons (receptors)
  2. Motor neurons (effectors)
  3. Interneurons (interconnecting)

Definition: Myelin sheath - A fatty insulating layer around some axons that speeds up signal transmission.

Example: The thyroxine hormone, along with vitamin B12, plays a crucial role in the multiplication and division of neurons during embryonic development.

NERVOUS SYSTEM Endocrine System ↓ Slow speed coordination Nervous System + High speed coordination Homeastatic State (tendency of body to re

Action Potential Generation

The action potential is a key process in nervous system physiology, involving several stages:

  1. Polarization (Resting State): The neuron maintains a resting membrane potential of about -70mV.

  2. Depolarization: A stimulus causes sodium channels to open, allowing sodium ions to flow into the cell. This raises the membrane potential to the threshold level (about -55mV).

  3. Rising Phase: If the threshold is reached, more voltage-gated sodium channels open, causing a rapid influx of sodium ions. The membrane potential quickly rises to about +30 to +45mV.

  4. Repolarization: Potassium channels open, and potassium ions flow out of the cell. Simultaneously, sodium channels close. This causes the membrane potential to return towards the resting level.

  5. Hyperpolarization: The membrane potential briefly becomes more negative than the resting state due to the continued outflow of potassium ions.

Vocabulary: Threshold potential - The minimum membrane potential that triggers an action potential.

Highlight: The 7 steps of action potential involve polarization, depolarization, rising phase, peak, falling phase, repolarization, and hyperpolarization.

NERVOUS SYSTEM Endocrine System ↓ Slow speed coordination Nervous System + High speed coordination Homeastatic State (tendency of body to re

Brain Structure and Development

The brain develops from the neural tube, which forms five primary vesicles:

  1. Telencephalon (forms the cerebrum)
  2. Diencephalon (forms the thalamus and hypothalamus)
  3. Mesencephalon (forms the midbrain)
  4. Metencephalon (forms the pons and cerebellum)
  5. Myelencephalon (forms the medulla oblongata)

The cerebrum, the largest part of the brain, consists of gray matter (cortex) and white matter. It is divided into several lobes, each with specific functions:

  • Frontal lobe: Motor control, planning, reasoning
  • Parietal lobe: Sensory processing
  • Temporal lobe: Auditory processing, memory
  • Occipital lobe: Visual processing

Example: The Broca's area in the frontal lobe is responsible for speech production, while Wernicke's area in the temporal lobe is involved in language comprehension.

Highlight: Understanding the nervous system anatomy and physiology is crucial for comprehending how different brain regions contribute to various functions.

NERVOUS SYSTEM Endocrine System ↓ Slow speed coordination Nervous System + High speed coordination Homeastatic State (tendency of body to re

Factors Affecting Neuron Function

Several factors influence the functioning of neurons in the nervous system. Key among these are:

  1. Na-K pump (Active transport): This protein actively moves sodium and potassium ions across the cell membrane, maintaining the resting potential.

  2. Ion channels (Passive transport): These channel proteins allow specific ions to move across the membrane based on concentration gradients.

  3. Negatively charged proteins and associated anions: These contribute to the overall charge distribution across the neuron membrane.

The brain's functional areas play crucial roles in various processes:

  • Motor areas control movement
  • Sensory areas process incoming sensory information
  • Association areas integrate information and are involved in higher cognitive functions

Highlight: The balance of ions across the neuron membrane is critical for proper nervous system function and signal transmission.

NERVOUS SYSTEM Endocrine System ↓ Slow speed coordination Nervous System + High speed coordination Homeastatic State (tendency of body to re

Nervous System Components

The central nervous system (CNS) consists of the brain and spinal cord, which are protected by several layers:

  1. Dura mater: The outermost tough protective layer
  2. Arachnoid mater: The middle layer
  3. Pia mater: The innermost layer, closely adhering to the brain and spinal cord

The brain contains fluid-filled cavities called ventricles:

  1. Two lateral ventricles
  2. Third ventricle
  3. Cerebral aqueduct
  4. Fourth ventricle

Cerebrospinal fluid (CSF) is produced by the choroid plexus and circulates through these ventricles, providing cushioning and nutrients.

Definition: Choroid plexus - A network of blood vessels and cells in the ventricles that produces cerebrospinal fluid.

Highlight: The central nervous system is well-protected by meninges and bathed in cerebrospinal fluid, which provides both physical and chemical protection.

NERVOUS SYSTEM Endocrine System ↓ Slow speed coordination Nervous System + High speed coordination Homeastatic State (tendency of body to re

Limbic System and Hypothalamus

The limbic system is a group of interconnected structures involved in emotion, behavior, and memory. Key components include:

  1. Amygdala: Processes emotions, particularly fear and aggression
  2. Hippocampus: Crucial for forming new memories and spatial navigation

The hypothalamus is a small but vital structure that serves as a link between the nervous system and the endocrine system. Its functions include:

  1. Regulating behavior and emotions
  2. Controlling the endocrine system through the pituitary gland
  3. Thermoregulation
  4. Autonomic nervous system control
  5. Maintaining the body's biological clock

The olfactory system, responsible for the sense of smell, consists of:

  1. Olfactory bulbs: Receive input from olfactory receptors in the nose
  2. Olfactory tract: Transmits information to other brain areas
  3. Olfactory cortex: Processes and interprets smell information

Vocabulary: Olfactory - Relating to the sense of smell.

Highlight: The hypothalamus plays a crucial role in maintaining homeostasis by integrating nervous system function with endocrine system control.

NERVOUS SYSTEM Endocrine System ↓ Slow speed coordination Nervous System + High speed coordination Homeastatic State (tendency of body to re

Nervous System Overview

The nervous system is a vital component of the body's regulatory mechanisms, working in tandem with the endocrine system to maintain homeostasis. While the endocrine system provides slow-speed coordination, the nervous system offers high-speed coordination, allowing for rapid responses to stimuli.

The basic structural and functional unit of the nervous system is the neuron. Neurons consist of several key parts:

  1. Cyton (cell body or pericaryon): The main regulating part
  2. Dendrites: Processes that receive signals
  3. Axon: The main functional part for transmitting signals

Supporting the neurons are neuroglia cells, which provide essential functions such as packaging, protection, support, and nutrition to the neurons.

Vocabulary: Homeostasis - The tendency of the body to maintain a stable internal environment.

Highlight: The nervous system's ability to provide high-speed coordination is crucial for rapid responses to environmental changes and internal stimuli.

NERVOUS SYSTEM Endocrine System ↓ Slow speed coordination Nervous System + High speed coordination Homeastatic State (tendency of body to re

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Knowunity is the # 1 ranked education app in five European countries

Knowunity was a featured story by Apple and has consistently topped the app store charts within the education category in Germany, Italy, Poland, Switzerland and United Kingdom. Join Knowunity today and help millions of students around the world.

Ranked #1 Education App

Download in

Google Play

Download in

App Store

Knowunity is the # 1 ranked education app in five European countries

4.9+

Average App Rating

13 M

Students use Knowunity

#1

In Education App Charts in 12 Countries

950 K+

Students uploaded study notes

Still not sure? Look at what your fellow peers are saying...

iOS User

I love this app so much [...] I recommend Knowunity to everyone!!! I went from a C to an A with it :D

Stefan S, iOS User

The application is very simple and well designed. So far I have found what I was looking for :D

SuSSan, iOS User

Love this App ❤️, I use it basically all the time whenever I'm studying