C3.1

• Increasing size of hierachy :

  Cell -> Tissue -> Organ -> Organ system -> Organism.
• System integration :


  Process where different physiological systems in a body system work together to maintain homeostasis/perform a function.
• Communication of body systems :

  Hormones/Neurotransmitters allow for communication between different locations.
• Cells :


  Basic unit of life -> smallest structural unit able to sustain itself using energy.

  Able to differentiate to be adapted for certain functions.
• Tissues :

  Group of cells working together to perform a function.

  Can contain more than 1 type of cell -> similar structure.

  Cells must stick together (Blood exempt) & communicate to coordinate functions.

  4 basic types :

  • Connective -> support other tissue & bind them together (bone).
  • Epithelial -> provide a covering (skin).
  • Muscle -> contain striated muscles (skeletal movement) & smooth muscle.
  • Nerve -> transmit electrical impulses to/from various parts of the human body.
• Organs :


  Groups of tissue working together to perform a function.

  3 types in plants :

  • Roots -> Anchor plant, absorb water & store nutrients.
  • Stems -> Support plant & transport nutrrients.
  • Leaves -> Perform photosynthesis.
• Organ systems :


  Groups of organs working together to perform a function.

  E.g :

  • Nervous system.
  • Respiratory system.
  • Circulatory system.
• Organism :


  Living individual made of interconnected part.

  Interaction & coordination between organ systems allow organism to undergo processes needed for life.
• Emergent properties :

  Properties/behaviours that emerge that are not present in lower levels of a system (individual components making up the system).
• E.g of emergent properties :

  Cell -> life emerges.

  Tissue -> Heart tissue : work together to contract.

  Organ -> Heart : all tissues work together to pump blood.

  Organ system -> CV systems : components work together to transport blood throughout the body.

  Organism : Blood from CV system used to provide nutrients for different parts of body to allow for organism to reproduce & survive.
• E.g of system integration :

  Mouth : mixes food with saliva & chews it.

  Oesphagus : transports food to stomach.

  Stomach : churns & adds gastric acid to the food.

  Intestine : digest food & passes waste material.

  Anus : excretes waste products from food.
• Cheetah :


  Adaptations of cheetah are emergent properties.

  E.g :

  • Rings on tail to help with camouflage.
  • Longer & heavier hind limb bones to enable longer strides.
  • Spots on body to help with camouflage.
  • Large heart & lungs.
• Endocrine vs Nervous system :

  Endocrine :

  • Glands
  • Hormone molecules
  • Widespread.
  • Slow signal speed.
  • Long signal duration.
  • Involuntary.

  Nervous :

  • Brain, Spinal cord & Peripheral nerves.
  • Neurotransmitter between neurons & Electrical signal within neurons.
  • Short distance.
  • Fast signal speed.
  • Short signal duration.
  • Voluntary & Involuntary.
• Blood :


  All organs/tissues supplied with blood -> carry nutrients, oxygen, hormones & water -> used for metabolism.

  Removes waste products -> CO2 & Urea etc.

  Transported through CV system using tubes & heart.

  Capillaries allow for nutrient exchange.
• Nervous system :


  CNS & PNS -> CNS : spinal cord & brain and PNS : nerves connecting brain & spinal cord to the body.

  PNS :

  • SNS : Somatic -> regulate voluntary movements.
  • ANS : Autonomic -> regulate involuntary movements.
• Brain :

  Organ that acts as center of nervous system -> consists of nerve cells & glial cells.

  Perform unconscious & conscious processes.

  Centralises control over body -> rapid & coordinated response to many inputs.
• Receptors for brain :

  Conscious :

  • Photo : located in retina for light.
  • Chemo : located in tongue for chemicals.
  • Thermo : located in skin for information on changes to temperature.
  • Mechano : located ininner ear for sound vibrations.

  Unconscious :

  • Osmo : located in carotid arteries & hypothalamus for solute & water content in blood.
  • Baro : located in carotid arteries & aorta for blood pressure.
  • Propio : located in muscle & joints for balance & coordination.
• Structure of brain :

  Cerebrum : split into left & right hemisphere -> each contain 4 lobes = cerebral, frontal, occipital & temporal.

  • Conscious activity & lobes interact with each other -> each lobes control specific functions.
  • Vision/Hearing/Touch/Senses
  • Coordinate movement.

  Cerebellum : back of the head -> split into the left & right.

  • Coordinate voluntary movements.
  • Control balance & equilibrium.

  Brainstem : autonomic nervous system (mainly)

  • Pons connects midbrain to medulla.
  • Medulla controls involuntary processes.
  • Spinal chord as you move down.
  • Breathing & Heart rate.

  
• How does the brain communicate with body :

  Nerve impulses sent in/out of spinal cord from 31 paired nerves -> spinal nerves.

  Nerve impulses sent from brain’s own nerves -> cranial nerves -> 12 paired nerves connecting various body parts to brain through brainstem.
• Spinal cord :


  Neural pathway connecting body to brain, but is able to process information by itself (unconscious processes).

  Part of CNS.
• Conscious vs Unconscious processing :

  Conscious :

  • Occurs when awake only
  • Voluntary - intentionally carry out a process.
  • Coordinated by brain only
  • E.g : Contraction of skeletal muscles/Thought.

  Unconscious :

  • Occurs when awake/asleep.
  • Involuntary : can not intentionally cause/prevent a process.
  • Coordinated by brain & spinal cord.
  • E.g : Secretion by glands/Contraction of smooth muscle.
• Memory :


  Process of acquiring, storing, retaining & retrieving information.

  2 types :

  • Explicit - conscious collection of memories relating to factual information & personal information.
  • Implicit - memories collected unconsciously or automatically.
• Spinal cord :


  2 types of neural tissue : white & grey matter.

  White matter : composed of axons of neurons & carries neural impulses to/from brains.

  Grey matter : composed of neurons/synapses involving spinal cord integration.

  Sensory information enters grey matter and then motor information sent back -> pathway called reflex arc.
• Plasticity :


  Ability of neural networks to change due to new information/experiences.

  Brain is able to change from response to inputs through changes in neurons -> formation of new synapses, strengthening synapses/removal synapses.
• Sensory receptors & neurons :

  Help ‘feel’ sensations from the skin (physical stimuli) & convert them into electrical signals (action potential).

  Receptors are specialised cells that are able to pick up sensory stimuli & trasmit to sensory neurons.

  • Form of nerve endings or specialised cells.
• Types of receptors on skin :

  Mechano : Motion, pressure, touch, sound & stretches.

  Chemo : Chemical compounds.

  Thermo : Temperature.

  Noci : Pain.

  Electromagnetic : Electromagnetic energy -> light from photoreceptors.
• Example of a specific sensory pathway :

  Skin contain mechanoreceptor -> detect pressure.

  Touch item -> causes mechanoreceptors to generate & send action potential through sensory neurons.

  Sensory neuron joins one of 31 spinal nerves -> enter grey matter of spinal cord -> goes to brain (parietal lobe).

  Stimuli is interpreted -> causes response to be sent through white matter of spinal cord to effector.