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Ideas to cover


  • Nervous system continued
  • Respiratory system
  • Endocrine system

Human Nervous system


  • Peripheral Nervous system – Somatic nervous system
  • Cranial nerves: paired nerves originating directly from the brain
  • Spinal nerves: arise at intervals along the length of the spinal cord

– Autonomous nervous system

  •  Sympathetic nervous system
  • Parasympathetic nervous system




  • Glucose formed in the digestive system is used to provide energy for various life processes
  • This glucose is broken down with the help of oxygen, or without oxygen in certain cases (glycolysis)




  • The release of energy through aerobic respiration is a lot more than anaerobic respiration
  • The energy released during cellular respiration is immediately used to synthesize ATP which is later used to fuel all other activities in cell
  • Plants have the same respiration process too, but CO2 produced is utilized by photosynthesis process during the day
  • Terrestrial organisms have lower respiration rate than aquatic animals.




  • In terrestrial organisms, the oxygen needed for cellular respiration is absorbed by different organs
  • For maximum gaseous exchange: high surface area is needed
  • Gaseous exchange = thin delicate surface layer needed, so its usually protected within the body
  • To take gases in and out pathways are needed that should be protected too
  • So most higher terrestrial organisms have specialized respiratory system needed for this purpose


Respiratory system in Humans


Respiratory system in Humans


  • Nostrils:

– Entry point of air into human body

– Has fine hairs -> filtration system that traps dust

– Nasal passage lined with mucus membrane aiding dust and impurity trapping

  • Pharynx:

– where food pipe and wind pipe separate – Has epiglottis

  • Larynx:

– Voice box


Respiratory system in Humans


  • Trachea:

– Windpipe

– cartilaginous tube that connects the larynx to the bronchi of the lungs – Ring of cartilage to prevent collapse of the air passage

  • Bronchi:

– Pair of bronchus near root of lungs – Get divided into smaller branches

  • Bronchioles:

– smaller branches of the bronchial airways in the respiratory tract • Alveoli:

– Baloon like structures providing a large surface where gasous exchange takes place

– Walls have extensive system of blood vessels • Diaphragm/thoracic diaphragm

– Located below the lungs

– Muscle that causes lungs to expand and contract for respiration


Respiratory system in Humans



Respiratory system in Humans


  • The process of regulation of breathing is adjusted by the pons and medulla oblongata. There is a chemically sensitive region near them that is highly sensitive to CO2 and hydrogen ions
  • Increase in these can activate this centre -> signal to brain to increase respiration rate -> signal sent to diaphragm


Endocrine system


  • Another system of control and co-ordination parallel to nervous system
  • But pituitary gland makes as a bridge between the both • Secretions in this gland
  • A system of chemical signal waves • Consists of endocrine glands
  • EG -> lack duct (ductless gland) secreting chemicals called “hormones” directly in the blood stream
  • Different organisms have different number and types of EGs


Endocrine system

Endocrine system


  • Hypothalamus:

– Releases releasing hormones to pituitary and causes pituitary to release hormones e.g.

  • ACTH releasing hormone
  • Growth hormone releasing hormone • Somatostatin etc.
  • Pituitary gland:

– Master gland – as its secretions controls almost every endocrine gland – Some important hormones include:

  • Growth hormone • LH and FSH
  • TSH (thyroid stimulating hormone) • ACTH
  • Oxytocin
  • Vasopressin or antidiuretic hormone


Endocrine system


  • Pineal Gland:

– Melatonin – circadian rythm • Thyroid gland

– T3 (thyroxine)

– T4 (triiodothyronine)

– Calcitonin -> decrease amount of calcium in blood • Parathyroid

– Parathormone -> increases calcium in blood • Adrenal gland:

– Cortisol

– Aldosterone

– Some sex hormones

– Adrenaline and noradrenaline


Endocrine system

  • Pancreas:

– Insulin

– Glucagon

  •  Kidneys:

– Erythropoietin

  •  Ovaries:

– Oestrogens

– Progesterone

– Relaxin

  • Testes:

– Testesterone