Biopsychology summary

Biopsychology:

The nervous system:

• The nervous system: specialised network of cells in the human body and is our primary internal communication system.

• Two main functions are:

  • To collect, process and respond to environmental information.

  • To coordinate the working of different organs and cells in the body.

• It is divided into two sub-systems:

  • CENTRAL NERVOUS SYSTEM (CNS)

    • Made up of the brain and spinal cord.

    • The cerebral cortex (outer layer) is highly developed and distinguishes us from other animals.

    • Spinal cord is responsible for reflex actions.

    • Passes messages to and from the brain and connects nerves to the PNS.

  • PERIPHERAL NERVOUS SYSTEM (PNS)

    • Transmits messages, via neurons

    • PNS is divided into:

    • Autonomic nervous system (ANS) which governs vital functions in the body e.g. breathing and stress responses.

    • 

      Somatic nervous system (SNS) which controls muscle movement and receives information from sensory receptors

The endocrine system:

• The endocrine system: works alongside the nervous system to control vital functions in the body via hormones.

• Works slower than nervous system but it is widespread and has powerful effects.

• Glands are organs in the body that produce hormones

  • Major endocrine gland is the pituitary gland (‘master gland’). It controls the release of hormones from all the other endocrine glands in the body.

• Hormones are secreted into the bloodstream and affect any cell in the body that has a receptor for that hormone.

  • Thyroxine produced by the thyroid gland affects cells in the heart and cells throughout the body which increase metabolic rates (affects growth rates).

• Endocrine & ANS work together (fight or flight)

  • When a stressor is perceived, the hypothalamus triggers activity in the sympathetic branch of the ANS. It changes from its normal resting state (parasympathetic state) to the physiologically aroused sympathetic state.

  • Adrenaline is released from the adrenal medulla into the bloodstream.

  • Adrenaline triggers physiological changes in target organs in the body. This is called the fight or flight response.

  • Once the threat has passed the parasympathetic nervous system returns the body to its resting state (rest and digest).

The structure and functions of neurons:

• Neurons transmit signals electrically and chemically and provide the nervous system with its primary means of communication.

• Three types of neurons:

  • MOTOR NEURONS connect the CNS to effectors e.g. muscles and glands. They have short dendrites and long axons.

  • SENSORY NEURONS carry message from the PNS to the CNS. They have long dendrites and short axons.

  • RELAY NEURONS connect sensory neurons to motor or other relay neurons. They have short dendrites and short axons.

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  Structure:

  • Cell body (soma) includes which contains the genetic material of the cell.

  • Dendrites are branch-like structures that protrude from the cell body. These carry nerve impulses from neighbouring neurons towards the cell body.

  • Axons carry electrical impulses away from the cell body down the length of the neuron.

    • Covered in a fatty layer of myelin sheath that protects the axons.

    • Gaps in the axons called nodes of Ranvier speed up the transmission of the impulse.

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