Integration of Body Systems (IB Topic C3.1)

Essential Idea(s): The integration of body systems in multicellular organisms includes hierarchical organization, coordinated hormonal and nervous signaling, and feedback mechanisms to ensure the emergence of complex functions necessary for survival.

Unit Length: 6 Lessons (+4 AHL)

Guiding Questions

◊ What are the roles of nerves and hormones in integration of body systems?

◊ What are the roles of feedback mechanisms in regulation of body systems?

Materials:

Self-Teaching Slides (SL) / Self-Teaching Slides (AHL)	Notes Template (SL) / Notes Template (AHL)
Teaching Slides (SL)

IB Statement(s) and Objective(s)
C3.1.1: System integration Define system integration (of body systems) Explain why system integration is needed to perform the functions of life Compare a reductionist approach vs. systems approach to studying biology C3.1.2: Cells, tissues, organs and body systems as a hierarchy of subsystems that are integrated in a multicellular living organism Define tissue, organ and organ systems State examples of emergent properties at each level of organization within a multicellular organism C3.1.3: Integration of organs in animal bodies by hormonal and nervous signalling and by transport of materials and energy State the two primary mechanisms by which animals integrate organ systems State the function of the nervous system State the function of the following neuron cell parts: dendrites, axon and cell body State the function of the endocrine system State the function of hormones Compare the following between the nervous system and endocrine systems: signal speed, signal duration, signal mechanism of travel, effector response Outline the role of blood in the transport of material and energy between organs C3.1.4: The brain as a central information integration organ State the function of the brain List sources of information input to the brain Outline the processes of learning and memory in the brain C3.1.5: The spinal cord as an integrating centre for unconscious processes List organs of the central nervous system Outline the two main tissues types of the central nervous system Compare and contrast conscious and unconscious processing State that the spinal cord can only coordinate unconscious processes C3.1.6: Input to the spinal cord and cerebral hemispheres through sensory neurons State the 3 main types of neurons Outline the function of sensory receptors C3.1.7: Output from the cerebral hemispheres to muscles through motor neurons Outline the function of motor neurons C3.1.8: Nerves as bundles of nerve fibres of both sensory and motor neurons Define nerve Describe the structures visible in a nerve transverse cross section State that nerves can contain either or both sensory and motor neurons C3.1.9: Pain reflex arcs as an example of involuntary responses with skeletal muscle as the effector Define reflex and reflex arc Outline the steps of a reflex arc stimulation + response C3.1.10: Role of the cerebellum in coordinating skeletal muscle contraction and balance Identify the cerebellum on a diagram of the human brain State the function of the cerebellum C3.1.11: Modulation of sleep patterns by melatonin secretion as a part of circadian rhythms Describe the secretion and action of melatonin Outline the mechanism that regulates melatonin secretion in response to the day-night cycle C3.1.12: Epinephrine (adrenaline) secretion by the adrenal glands to prepare the body for vigorous activity State the main evolutionary function of epinephrine Outline the mechanism of action of epinephrine as a signaling molecule Outline the effects of epinephrine on the body C3.1.13: Control of the endocrine system by the hypothalamus and pituitary gland Outline the role of the hypothalamus as a link between nervous and endocrine systems Outline the role of the pituitary gland as a hormone releasing system List body processes that are monitored by the hypothalamus C3.1.14: Feedback control of heart rate following sensory input from baroreceptors and chemoreceptors Outline the structures and functions of nervous tissue that can regulate heart rate Outline the role of the accelerator nerve and the vagus nerve Outline the role of baroreceptors and chemoreceptors in regulating heart rate C3.1.15: Feedback control of ventilation rate following sensory input from chemoreceptors State the effect of exercise on CO2 production Outline the relationship between CO2 production and blood pH Outline the feedback loop that regulates the rate of ventilation C3.1.16: Control of peristalsis in the digestive system by the central nervous system and enteric nervous system Outline the role of peristalsis in the digestive process Outline the roles of the central and enteric nervous systems (ENS) in movement of material into, through and out of the gut
Additional Higher Level Topics C3.1.17: Observations of tropic responses in seedlings Define tropism and phototropism State two external factors that control the growth of roots and stems Contrast positive and negative tropism Nature of Science (NOS): Explain the utility and differences between qualitative and quantitative data Explain the differences between accuracy and precision Explain the concept of uncertainty and outline its use in experimental procedures C3.1.18: Positive phototropism as a directional growth response to lateral light in plant shoots Outline the cause and consequence of positive phototropism in a plant shoot Define phototropism and gravitropism Contrast positive and negative tropism C3.1.19: Phytohormones as signalling chemicals controlling growth, development and response to stimuli in plants Define phytohormone Outline role of phytohormones in plant growth, development and response to stimuli C3.1.20: Auxin efflux carriers as an example of maintaining concentration gradients of phytohormones State two roles of the hormone auxin Outline the role of auxin in apical dominance Describe the mechanism of movement of auxin into and between plant cells C3.1.21: Promotion of cell growth by auxin Explain how auxin concentrations allow for tropisms Describe the mechanism of action of auxin in phototropism, including the role of H+ ions C3.1.22: Interactions between auxin and cytokinin as a means of regulating root and shoot growth Outline the source and transport of auxin and cytokinin in plants Explain how root and shoot growth are regulated by the interaction of auxin and cytokinin C3.1.23: Positive feedback in fruit ripening and ethylene production Describe the positive feedback mechanism of ethylene in fruit ripening Outline why fruit ripening evolved to be rapid and synchronized

IB Statement(s) and Objective(s)

C3.1.1: System integration

Define system integration (of body systems)
Explain why system integration is needed to perform the functions of life
Compare a reductionist approach vs. systems approach to studying biology

C3.1.2: Cells, tissues, organs and body systems as a hierarchy of subsystems that are integrated in a multicellular living organism

Define tissue, organ and organ systems
State examples of emergent properties at each level of organization within a multicellular organism

C3.1.3: Integration of organs in animal bodies by hormonal and nervous signalling and by transport of materials and energy

State the two primary mechanisms by which animals integrate organ systems
State the function of the nervous system
State the function of the following neuron cell parts: dendrites, axon and cell body
State the function of the endocrine system
State the function of hormones
Compare the following between the nervous system and endocrine systems: signal speed, signal duration, signal mechanism of travel, effector response
Outline the role of blood in the transport of material and energy between organs

C3.1.4: The brain as a central information integration organ

State the function of the brain
List sources of information input to the brain
Outline the processes of learning and memory in the brain

C3.1.5: The spinal cord as an integrating centre for unconscious processes

List organs of the central nervous system
Outline the two main tissues types of the central nervous system
Compare and contrast conscious and unconscious processing
State that the spinal cord can only coordinate unconscious processes

C3.1.6: Input to the spinal cord and cerebral hemispheres through sensory neurons

State the 3 main types of neurons
Outline the function of sensory receptors

C3.1.7: Output from the cerebral hemispheres to muscles through motor neurons

Outline the function of motor neurons

C3.1.8: Nerves as bundles of nerve fibres of both sensory and motor neurons

Define nerve
Describe the structures visible in a nerve transverse cross section
State that nerves can contain either or both sensory and motor neurons

C3.1.9: Pain reflex arcs as an example of involuntary responses with skeletal muscle as the effector

Define reflex and reflex arc
Outline the steps of a reflex arc stimulation + response

C3.1.10: Role of the cerebellum in coordinating skeletal muscle contraction and balance

Identify the cerebellum on a diagram of the human brain
State the function of the cerebellum

C3.1.11: Modulation of sleep patterns by melatonin secretion as a part of circadian rhythms

Describe the secretion and action of melatonin
Outline the mechanism that regulates melatonin secretion in response to the day-night cycle

C3.1.12: Epinephrine (adrenaline) secretion by the adrenal glands to prepare the body for vigorous activity

State the main evolutionary function of epinephrine
Outline the mechanism of action of epinephrine as a signaling molecule
Outline the effects of epinephrine on the body

C3.1.13: Control of the endocrine system by the hypothalamus and pituitary gland

Outline the role of the hypothalamus as a link between nervous and endocrine systems
Outline the role of the pituitary gland as a hormone releasing system
List body processes that are monitored by the hypothalamus

C3.1.14: Feedback control of heart rate following sensory input from baroreceptors and chemoreceptors

Outline the structures and functions of nervous tissue that can regulate heart rate
Outline the role of the accelerator nerve and the vagus nerve
Outline the role of baroreceptors and chemoreceptors in regulating heart rate

C3.1.15: Feedback control of ventilation rate following sensory input from chemoreceptors

State the effect of exercise on CO2 production
Outline the relationship between CO2 production and blood pH
Outline the feedback loop that regulates the rate of ventilation

C3.1.16: Control of peristalsis in the digestive system by the central nervous system and enteric nervous system

Outline the role of peristalsis in the digestive process
Outline the roles of the central and enteric nervous systems (ENS) in movement of material into, through and out of the gut

Additional Higher Level Topics

C3.1.17: Observations of tropic responses in seedlings

Define tropism and phototropism
State two external factors that control the growth of roots and stems
Contrast positive and negative tropism
Nature of Science (NOS): Explain the utility and differences between qualitative and quantitative data
Explain the differences between accuracy and precision
Explain the concept of uncertainty and outline its use in experimental procedures

C3.1.18: Positive phototropism as a directional growth response to lateral light in plant shoots

Outline the cause and consequence of positive phototropism in a plant shoot
Define phototropism and gravitropism
Contrast positive and negative tropism

C3.1.19: Phytohormones as signalling chemicals controlling growth, development and response to stimuli in plants

Define phytohormone
Outline role of phytohormones in plant growth, development and response to stimuli

C3.1.20: Auxin efflux carriers as an example of maintaining concentration gradients of phytohormones

State two roles of the hormone auxin
Outline the role of auxin in apical dominance
Describe the mechanism of movement of auxin into and between plant cells

C3.1.21: Promotion of cell growth by auxin

Explain how auxin concentrations allow for tropisms
Describe the mechanism of action of auxin in phototropism, including the role of H+ ions

C3.1.22: Interactions between auxin and cytokinin as a means of regulating root and shoot growth

Outline the source and transport of auxin and cytokinin in plants
Explain how root and shoot growth are regulated by the interaction of auxin and cytokinin

C3.1.23: Positive feedback in fruit ripening and ethylene production

Describe the positive feedback mechanism of ethylene in fruit ripening
Outline why fruit ripening evolved to be rapid and synchronized


Activities: ⓟ = podcast / ⍰ = inquiry 5 / ⓦ = Write it / Ӕ = The academy / Ⓡ = Read it
Ⓛ: Play-doh Modeling – Neurons (💁/ 👭 max 2) Use playdough to make a model of a reflex arc, complete with a sensory neuron, integration center (the CNS), motor neuron, and effector (AHL students, include myelination on the CNS neuron). Place your model on a piece of paper, and label: dendrites, cell body, nucleus, axon, synaptic terminus, motor end plates / synaptic buttons, Myelin, Schwann cell, Node of Ranvier. Take a photo of the model from above, then submit to G. Classroom. ⓟ: Feeling No Pain – A Gift, or a Curse? 👫 (max 3) Congenital Insensitivity to Pain (CIP) is a condition with a complicated-sounding name, but a simple effect: people who have it can feel little to no pain. Scientists are finding ways to help people with this condition feel pain for the first time. Is this a gift, or a curse? Together with your fellow podcasters, begin by explaining how pain works, including all terms and concepts from this unit. Then, discuss the benefit of pain – why does pain exist in the first place? Would humans and animals be better off without pain? Should scientists try to “fix” those who cannot feel pain? Ⓛ: Phototropism vs. Gravitropism 👫 (max 2) Get a hold of some basic bean or cereal seedlings, and design a lab demo to show the effects of phototropism and gravitropism. Try to show both positive and negative gravitropism, and brainstorm ways to show the effects on shoots (above ground) and roots (below ground). ⓟ/ⓦ: Case Studies in Hormones (💁/ 👭 max 2) Choose any one of the following case studies, and as a group, read and discuss the questions in each of the sections of the scenario you choose: Scenario 1: Hot and Bothered: A Case of Endocrine Disease Scenario 2: What’s Wrong with Timothy? A Case Study on the Endocrine System Scenario 3: Chemical Eric: Dealing with the Disintegration of Central Control ⓦ: “Inquiry 5”: The Hormones of Homeostasis (💁/ 👭 max 2) Create a list of 5 inquiry questions related to homeostasis. Remember that good inquiry questions are conceptual / open-ended…such as: “What role do feedback loops play in homeostasis?; NOT: “What is melatonin?” If working solo, write out answers to your own questions; if working in pairs, record yourselves asking each other your 5 questions. Ⓛ: Microscope It: Neurons 👭 (max 2) Grab a microscope and some slides of brain/nervous tissue. Sketch or photograph what you see, and write at least 5 good inquiry questions about the structure. How does its structure help fulfill its role? Answer your own questions, either in writing or in a recorded video. Try to explain using as many terms and concepts from B9.1 as possible. Ӕ: YouTube Narrator – The Nervous System 💁 Find a short video on YouTube with nice visuals of the human nervous system (try to find one that covers as much of B9.1 as possible, with visuals of the CNS, PNS, and diagrams of motor/relay/sensory neurons). Mute the audio and instead record yourself using the visuals to teach a brief lesson on how the nervous system works. Draw it Out: When Homeostasis Fails, Death Nears 👫 (max 2) Draw out (or search for a Google image) pictures of two separate people in two different environments – one at risk of hypothermia, and one at risk of heat stroke. For each person, label the specific parts of the body that are working to maintain homeostasis, and describe their functions. Explain how and why a failure of temperature control can result in a subsequent failure in systems integration. Ⓛ (AHL): Modeling Neurons with Black-Eyed Peas Complete the following cookbook lab to model the action of a neuron using black eyed peas. Answer each question at the end (remember that each person must answer their own questions!) (AHL) Plant hormones. Watch this video and answer these questions. 1) How do we know that auxin is produced at the tip of the shoot? 2) Where does the auxin travel to? 3) Where is the phytohormone cytokinin produced? 4) How is it transported up to the shoots in the plants? 5) If there is a greater ratio of auxin to cytokinin, what occurs? 6) If there is a greater ratio of cytokinin to auxin, what occurs? 7) What is the function of ethylene? 8) The more the fruit ripens, the more ethylene is produced. What type of feedback mechanism is this?