Biology · Interaction and interdependence
C3.1 — Integration of body systems
Biology · SL / HL · syllabus-mapped notes
C3.1.1
System integration
Explain system integration and its dependence on communication between components.
C3.1.2
Cells, tissues, organs and body systems as a hierarchy of subsystems that are integrated in a multicellular living organism
Explain the hierarchy from organelles to organism, and why emergent properties arise.
C3.1.3
Integration of organs in animal bodies by hormonal and nervous signalling and by transport of materials and energy
Contrast hormonal and nervous signalling, and explain transport by the circulatory system.
C3.1.4
The brain as a central information integration organ
Explain the brain's four roles as the central integrating organ.
C3.1.5
The spinal cord as an integrating centre for unconscious processes
Contrast unconscious and conscious processes, and where each is coordinated.
C3.1.6
Input to the spinal cord and cerebral hemispheres through sensory neurons
Explain how sensory input reaches the spinal cord and cerebral hemispheres.
C3.1.7
Output from the cerebral hemispheres to muscles through motor neurons
Explain how motor output reaches muscles from the cerebral hemispheres.
C3.1.8
Nerves as bundles of nerve fibres of both sensory and motor neurons
Describe nerves as bundles of sensory and motor fibres.
C3.1.9
Pain reflex arcs as an example of involuntary responses with skeletal muscle as the effector
Explain the pain reflex arc and its five components.
C3.1.10
Role of the cerebellum in coordinating skeletal muscle contraction and balance
Explain what the cerebellum does, and what it does not do.
C3.1.11
Modulation of sleep patterns by melatonin secretion as a part of circadian rhythms
Explain how melatonin modulates sleep, and how the rhythm stays synchronized with day and night.
C3.1.12
Epinephrine (adrenaline) secretion by the adrenal glands to prepare the body for vigorous activity
Explain how epinephrine redistributes blood to prepare for vigorous activity.
C3.1.13
Control of the endocrine system by the hypothalamus and pituitary gland
Explain how the hypothalamus and pituitary control the endocrine system.
C3.1.14
Feedback control of heart rate following sensory input from baroreceptors and chemoreceptors
Explain feedback control of heart rate from baroreceptors and chemoreceptors.
C3.1.15
Feedback control of ventilation rate following sensory input from chemoreceptors
Explain feedback control of ventilation rate, and why pH is what is monitored.
C3.1.16
Control of peristalsis in the digestive system by the central nervous system and enteric nervous system
Explain peristalsis, and how the enteric and central nervous systems divide control.
C3.1.17
Observations of tropic responses in seedlings
Observe tropic responses in seedlings, distinguishing qualitative from quantitative measures.
C3.1.18
Positive phototropism as a directional growth response to lateral light in plant shoots
Explain positive phototropism as differential growth, and its benefit.
C3.1.19
Phytohormones as signalling chemicals controlling growth, development and response to stimuli in plants
Explain what phytohormones control, with examples.
C3.1.20
Auxin efflux carriers as an example of maintaining concentration gradients of phytohormones
Explain how auxin efflux carriers and the acid trap build a concentration gradient.
C3.1.21
Promotion of cell growth by auxin
Explain how auxin acidifies the cell wall to allow it to extend.
C3.1.22
Interactions between auxin and cytokinin as a means of regulating root and shoot growth
Explain apical dominance as the interaction of auxin and cytokinin.
C3.1.23
Positive feedback in fruit ripening and ethylene production
Explain the positive feedback loop between ethylene and fruit ripening.