Nervous System Overview

Central Nervous System (CNS)

• Consists of the brain and spinal cord
• Protected by the blood-brain barrier, a specialized barrier that separates the CNS from the bloodstream
• Functions:
  • Integrates and processes information
  • Interprets and responds to sensory input
  • Controls voluntary movements
  • Regulates various bodily functions (e.g. heart rate, blood pressure)

Peripheral Nervous System (PNS)

• Consists of nerves that connect the CNS to the rest of the body
• Divided into:
  • Somatic Nervous System (SNS): controls voluntary movements
  • Autonomic Nervous System (ANS): controls involuntary functions (e.g. heart rate, digestion)
• Functions:
  • Transmits information between the CNS and the rest of the body
  • Controls muscle movements and sensory functions

Brain

• Divided into:
  • Cerebrum: largest part of the brain, responsible for higher-level functions (e.g. thought, emotion, movement)
  • Cerebellum: coordinates muscle movements and balance
  • Brainstem: connects the cerebrum and cerebellum to the spinal cord, regulates basic functions (e.g. breathing, heart rate)
• Functions:
  • Controls higher-level functions (e.g. thought, emotion, movement)
  • Regulates bodily functions (e.g. heart rate, blood pressure)

Spinal Cord

• Extends from the base of the brain down to the lower back
• Functions:
  • Transmits information between the brain and the rest of the body
  • Controls reflexes and automatic functions (e.g. withdrawal from pain)

Nerve Cells (Neurons)

• Basic units of the nervous system
• Consist of:
  • Dendrites: receive signals
  • Cell body: contains the nucleus and maintains the cell
  • Axon: transmits signals away from the cell body
• Functions:
  • Transmit and process information
  • Allow for communication between different parts of the nervous system

Central Nervous System (CNS)

• Comprises the brain and spinal cord
• Protected by the blood-brain barrier
• Integrates and processes information
• Interprets and responds to sensory input
• Controls voluntary movements
• Regulates various bodily functions, such as heart rate and blood pressure

Peripheral Nervous System (PNS)

• Consists of nerves connecting the CNS to the rest of the body
• Divided into Somatic Nervous System (SNS) and Autonomic Nervous System (ANS)
• SNS controls voluntary movements
• ANS controls involuntary functions, such as heart rate and digestion
• Transmits information between the CNS and the rest of the body
• Controls muscle movements and sensory functions

Brain Structure

• Divided into cerebrum, cerebellum, and brainstem
• Cerebrum: responsible for higher-level functions, such as thought, emotion, and movement
• Cerebellum: coordinates muscle movements and balance
• Brainstem: connects the cerebrum and cerebellum to the spinal cord, regulates basic functions, such as breathing and heart rate

Spinal Cord

• Extends from the base of the brain down to the lower back
• Transmits information between the brain and the rest of the body
• Controls reflexes and automatic functions, such as withdrawal from pain

Nerve Cells (Neurons)

• Basic units of the nervous system
• Comprise dendrites, cell body, and axon
• Dendrites: receive signals
• Cell body: contains the nucleus and maintains the cell
• Axon: transmits signals away from the cell body
• Transmit and process information
• Allow for communication between different parts of the nervous system

Optics and Vision

• The cornea is the transparent outer layer of the eye.
• The iris is the colored part that regulates the amount of light entering the eye.
• The lens changes shape to focus light on the retina.
• The retina contains light-sensitive cells called photoreceptors.
• Light refraction occurs at the cornea and lens, focusing on the retina.
• Photoreceptors in the retina convert light into electrical signals.
• These signals are transmitted to the optic nerve and interpreted by the brain as visual information.

Sensory Receptors

• Mechanoreceptors detect pressure, vibration, and stretch.
• Thermoreceptors detect temperature changes.
• Nociceptors detect painful stimuli.
• Photoreceptors detect light and enable vision.
• Chemoreceptors detect chemicals and enable taste and smell.
• Sensory receptors convert environmental stimuli into electrical signals.
• These signals are transmitted to the CNS for interpretation.

Peripheral Nervous System (PNS)

• The PNS consists of the somatic nervous system and autonomic nervous system.
• The somatic nervous system controls voluntary muscle movements.
• The autonomic nervous system regulates involuntary functions, such as heart rate and digestion.
• The PNS transmits signals from sensory receptors to the CNS.
• It also transmits motor signals from the CNS to muscles and glands.

Central Nervous System (CNS)

• The CNS consists of the brain and spinal cord.
• The CNS integrates and interprets sensory information.
• It controls voluntary movements and regulates involuntary functions.
• The CNS receives and processes information from sensory receptors.
• It also sends signals to muscles and glands to respond to stimuli.

Hormone Regulation

• Hormones are chemical messengers produced by endocrine glands.
• Hormones regulate various bodily functions, such as growth and development.
• Negative feedback mechanisms maintain homeostasis by regulating hormone levels.
• Hormone levels increase or decrease in response to changes in target cells.

Endocrine System

• The pituitary gland regulates growth and development.
• The thyroid gland regulates metabolism.
• The adrenal glands regulate the stress response.
• The pancreas regulates blood sugar levels.
• The endocrine system regulates growth and development.
• It maintains homeostasis and responds to stress and environmental changes.
• Hormones secreted by endocrine glands travel through the bloodstream to reach target cells.