Revision

• Type of sensory receptors

  • Photoreceptors
  • Thermoreceptors
  • Chemoreceptors
  • Mechanoreceptors
  • Nocireceptors
• Cerebrum

  • The outer layer of the brain and the largest part
  • Site of integration (receives information from senses and produces a response)
  • Surface covered in sulci (valleys) and gyri (peaks)
  • The outer layer is called the cerebral cortex (divided into 4 lobes)
  • Broken into 2 hemispheres (left and right) – connected by the corpus callosum
• Diencephalon

  • Interbrain – deep within the brain
  • Connects the cerebrum to the brainstem
  • Contains the thalamus (regulates consciousness) and hypothalamus (maintains homeostasis)
  • Also contains pituitary gland (master endocrine gland) that control other hormone-releasing glands
• Brainstem

  • Attaches the spinal cord to the cerebrum
  • Responsible for basic functions (breathing, circulation, digestion)
  • Determines where information entering and leaving the brain needs to go
  • Made up of midbrain, pons and medulla oblongata
• Cerebellum

  • Latin for “little brain”
  • Located at the back of the brain

  Responsible for:

  • Everyday voluntary functions e.g. walking and writing
  • Muscle memory
  • Muscle coordination (helps with balance)
• Cerebrum - Left Hemisphere

  • Sensory stimulus from the right side of the body
  • Motor control of the right side of the body
  • Speech, Language and Comprehension
  • Analysis and Calculations
  • Time and sequencing
  • Recognition of words, letters and numbers
• Cerebrum - Right Hemisphere

  • Sensory stimulus from the left side of the body
  • Motor control of the left side of the body
  • Creativity
  • Spatial ability
  • Context/perception
  • Recognition of places, faces and objects
• Lobes of the Brain

  1. Frontal Lobe
  2. Parietal Lobe
  3. Temporal Lobe
  4. Occipital Lobe
• Parietal Lobe

  Location: Upper middle part of the brain

  Responsible for:

  • Receiving most sensory information (touch, hot, cold etc)
  • Processing sensory information about temperature, taste, touch and movement
  • Helps you understand what is around you (spatial awareness)
  • Allows us to understand speech
  • Involved in reading, writing, and solving math problems
• Frontal Lobe

  Location: front part of the brain

  Responsible for cognitive functions and voluntary movements including:

  • Decision making
  • Planning and organising activities (executive functioning)
  • Controls voluntary muscle movements (e.g. moving your arms and legs)
  • Influences personality and behaviour
  • Broca's area in the frontal lobe helps produce speech (how we move our tongue to create sounds)
• Temporal Lobe

  Location: sides of the brain, near the temples

  Responsible for:

  • Receiving and interpreting auditory information (hearing)
  • Receiving and interpreting olfactory information (smell)
  • Development of memories (also changes short and long-term memory)
  • Involved in processing emotions (fear and anxiety) and some aspects of behaviour
• Occipital Lobe

  Location: Back part of the brain

  Responsible for receiving and interpreting visual information (see)
• Homeostasis

  Homeostasis is the body's way of maintaining a stable internal environment to ensure we don't fall ill. This is done mainly through the negative feedback loop.
• The brain and spinal cord are involved in the CNS
• The nerves branching off the brain and spinal cord are part of the PNS
• Types of neurons involved in the CNS

  • Motor Neuron - Communicates information from the brain to tissues and organs, allowing for movement
  • Interneuron - Transmits information between the sensory and motor neurons
• Types of Neurons in the PNS

  • Sensory Neurons - Send impulses from the PNS to the CNS
  • Motor Neurons - Send impulses from the CNS to the PNS
• Functions of the CNS

  The CNS receives information from the body, processes it, decides what to do, and sends an impulse to the PNS to perform the action
• Functions of the PNS

  The PNS receives information from the environments, sends it to the CNS, and passes impulses from the CNS back to body parts to perform actions
• Fight or flight responses

  During a dangerous situation, adrenaline floods the bloodstream, causing increased strength and rate of heartbeats, raised blood pressure, and speeding the conversion of glycogen into glucose to provide energy to the muscles. The adrenaline prepares bodies for the extra effort needed to defend (fight), run away (flight), or hide (freeze).
• Neurons


  Neurons are nerve cells that send electrical messages (impulses) to and from the brain. Impulses control movements and senses in our body.
• Function of a motor neuron

  Motor neurons communicate information from the brain to tissues and organs throughout the body, allowing for movement
• Function of a sensory neuron

  Sensory neurons take information from the environment and send them to the brain.
• Function of interneurons

  Interneurons transmit information between the sensory and motor neurons.
• Function of the Myelin Sheath

  The Myelin sheath helps to protect the axon from damage, as well as speed up the process of sending the message across the neuron as it stops the voltage from leaking out.
• Neurotransmitters

  A neurotransmitter is a chemical substance that is released at the end of a nerve fibre by the arrival of a nerve impulse and, by diffusing across the synapse or junction, affects the transfer of the impulse to another nerve fibre, muscle fibre, or other structure.
• Process of Nerve impulse transmission along a neuron


  1. Dendrites receive impulses from other neurons
  2. The impulse is sent to the cell body, where it processes it and decides whether the message should be passed along
  3. The message travels through the axon, across the neuron and to the end of the neuron (axon terminal)
  4. The impulse travels to the next neuron via the synapse.
• Voluntary vs Involuntary responses

  Voluntary responses are actions or reactions that are consciously controlled and initiated by the individual meaning they involve deliberate decision making e.g. walking, speaking, writing. Involuntary responses, however, are automatic, unconscious actions that the body performs without conscious control e.g. heartbeat, digestion, reflexes
• Stimulus, sense organ, effector, and response when you touch a hot plate

  Stimulus: The hot plate

  Sense organ: Hand, fingertips, and skin

  Effector: Muscles in the arms and hand

  Response: The hand quickly pulls away from the hot plate.
• Reflex

  An involuntary, rapid response to stimuli that aims to reduce the chances of harm to the body. It usually happens before you can process what is happening
• Reflex arcs

  Reflex arcs are the pathways of impulses during a reflex:

  1. A receptor detects a stimulus and sends an impulse to a nearby sensory neuron.
  2. Sensory neurons pass the impulse to interneurons (in the spinal cord)
  3. Interneurons send two messages simultaneously: one to the brain and the other to the effectors (usually the muscles) via motor neurons.
• Endocrine System

  The endocrine system secretes chemical messengers called hormones which travel in the blood and work on specific target cells to change/aid their function, thus coordinating bodily functions.
• Hormones vs Glands

  Glands are organs that produce and release substances such as hormones, into the bloodstream (e.g. thyroid and pituitary glands).

  Hormones, however, are chemical messages produced by glands that are carried in the blood and affect specific target cells  in various organs e.g. adrenaline, insulin, glucagon
• How hormones travel to their target organs

  Hormones are secreted by endocrine glands directly into the bloodstream. They travel throughout the body until they reach specific target organs or tissues. Target cells have specific receptors that are specific to particular hormones. When they bind, it triggers reactions within the cells.
• Pineal Gland

  Secretes:

  • Melatonin
• Pituitary Gland

  Secretes:

  • Oxytocin
  • Antidiuretic Hormone (ADH)
  • Growth Hormone (GH)
  • Luteinising Hormone
  • Prolactin
  • Thyroid Stimulating Hormone (TSH)
  • Follicle Stimulating Hormone (FSH)
  • Adrenocorticotropic Hormone (ACTH)
• Thyroid

  Secretes:

  • Thyroxine
  • Triiodothyronine
  • Parathyroid
• Thymus

  Secretes:

  • Thymosin
• Adrenal Glands

  Secretes:

  • Epinephrine
  • Norepinephrine
  • Glucacorticoids (cortisol)
  • Mineralocorticoids (Aldosterone)
• Pancreas

  Secretes

  • Insulin
  • Glucagon