SBI4U Success Criteria - Homeostasis PDF

Learning Goals Success Criteria Investigate the 1.​ I can use key terms: homeostasis, feedback feedback -​ Homeo= same , stasis= stable mechanisms that maintain -​ homeostasis: the process by which the body maintains a stable internal homeostasis in...

Learning Goals Success Criteria Investigate the 1.​ I can use key terms: homeostasis, feedback feedback -​ Homeo= same , stasis= stable mechanisms that maintain -​ homeostasis: the process by which the body maintains a stable internal homeostasis in environment living organisms; -​ organ systems involved: nervous system/brain, Endocrine System-pituitary and other glands (hormones), Muscular system, hair nails and skin, reproductive system, excretory system-kidneys -​ The Role of Circulation: -​ Transports nutrients and waste to maintain homeostasis -​ Transports hormones that stimulate responses to the effector -​ Regulate pH (carbon dioxide/carbonate buffering) -​ Effector in regulating body temperature 2.​ I understand the three elements of homeostatic mechanisms (sensor, integrator and effector) 1.​ sensor: detects changes in the internal or external environment 2.​ integrator: processes information from the sensor, and determines the response, the control center 3.​ effector: carries out the response, restores balance 3.​ I can define positive and negative feedback and provide examples of each in the human body negative: reverses a changes, restores conditions to their original state E.g. Maintaining body temperature, Maintaining blood pH, Return to resting heart rate after exercise positive: amplifies a change, Takes body further away from its normal condition E.g. labour and childbirth Hormone oxytocin causes contractions and stimulated by baby moving toward cervix causing more contractions Ends suddenly! In birth! the flight or fight response Adrenaline and other hormones are released to prime muscles and organ systems to fight or flee These hormones stimulates further release of adrenaline Ends when “stressor” is removed 4.​ I can explain the regulation of body temperature including the role of the hypothalamus.  Mechanism: controlled by the hypothalamus, which acts as a thermostat when cold: Sensor: thermoreceptors in skin Integrator: hypothalamus in brain Effector: -​ blood vessels in skin constrict to decrease blood flow, -​ Skeletal muscles contract uncontrollably(shivering) -​ Body hair stands on end to conserve heat Result: warming of body (turns off Hypothalamus) When Hot: Sensor: thermoreceptors in skin Integrator: hypothalamus in brain Effector: -​ blood vessels in skin dilate to increase blood flow, -​ sweat glands initiate sweating Result: cooling of body (turns off hypothalamus) 5.​ I can define homeotherms, endotherms and ectotherms and provide examples Homeotherm: Birds and humans, Maintain stable body temperature regardless of the temperature of the external environment. Endotherms: generates heat through metabolic process; usually homeotherms (eg: mammals) Ectotherms: depend on environmental heat sources; body temperature fluctuates (eg, reptiles, amphibians) demonstrate an 6.​ I can identify and explain the main divisions of the nervous system, including: CNS, PNS, understanding of autonomic, somatic, sympathetic and parasympathetic divisions. the anatomy and physiology of Main Functions of the nervous system: human body -​ To help the body maintain homeostasis systems, and -​ Quick and short-lived responses explain the -​ relays and processes information to different parts of the body mechanisms that enable the body to maintain CNS- Central Nervous System homeostasis -​ Consist of the brain and spinal cord functions: -​ process, interprets, and stores information from sensory inputs -​ generates motor outputs to control body activities -​ Governs higher-order functions such as thinking, memory, emotion, and reasoning brain: coordinates complex functions like thought, emotion, and voluntary movements spinal cord: acts as a relay between the brain and the peripheral nervous system; also controls reflex actions PNS-Peripheral Nervous system -​ Nerves extending from the CNS to the rest of the body functions: -​ transmits sensory information to the CNS -​ sends motor commands from the CNS to effectors (muscles, glands) Divisions: Autonomic Nervous System (ANS): -​ controls internal organs, blood vessels, and glands subdivisions: sympathetic: -​ fight or flight responses -​ prepares the body for emergencies: increases heart rate, dilated pupils, releases glucose, inhibits digestion parasympathetic: -​ rest and digest response -​ promotes relaxation: decrease heart rate, and conserves energy Somatic Nervous System: -​ controls skeletal muscles -​ transmits sensory signals from skin, muscles, and joints to the CNS 7.​ I can identify 3 types of neurons (sensory, interneuron and motor neuron) and identify the main parts of each cell. Sensory Neurons (Afferent Neurons): -​ Carry sensory information form receptors (eg. skin, eyes) to the CNS. -​ EX: transmit pain signals from your finger to your brain when you touch something sharp Interneurons (Association Neurons): -​ found within the CNS; connect sensory neurons to motor neurons -​ facilitate communication between sensory input and motor output Motor Neurons (Efferent Neurons): -​ Carry signals from the CNS to effectors like muscles or glands -​ EX: triggering your hand muscles to pull away from hot surface Parts of a Neuron: Dendrites: Branch-like structures that receive signals from other neurons or sensory receptors Cell Body (soma)-contains the nucleus; processes incoming signals. Axon: long fiber that transmits electrical impulses away from the cell body Myelin Sheath: insulating layer that speeds up signal transmission Anxo Terminal: End branches where the neuron communicates with other cells 8.​ I can explain how the action potential passes along an axon involving gated channels and sodium/potassium pumps. -​ a rapid electrical signal that travels along the axon of a neuron, enabling communication between cells. phases: Resting Potential: Voltage=70mV Maintained by the sodium-potassium pump (pump 3 Na out and 2K in) Threshold: stimulus raises the voltage to 55 mV, triggering the action potential Depolarization: Na channels open, and sodium ions rush into the axon, causing the inside to become positive (+40 mV)  Repolarization: K channels open, and potassium ions exit the axon, restoring a negative charge inside. Refactoring Period: Na/K pump restores ion balance; no new action potential can occur during this time Resting Potential Restored: The neuron is ready to fire again 9.​ I can label the parts of the brain and lobes of the cerebrum and identify their functions. 1.​ Cerebrum: -​ largest part of the brain -​ Frontal lobe: reasoning, decision making, voluntary movement, speech -​ Parietal lobe: processes sensory input (touch, temperature, pain) -​ Temporal lobe: hearing, memory, language comprehension -​ Occipital lobe: vision 2.​ Cerebellum: -​ coordinates balance, posture, and voluntary movements 3.​ Brainstem: -​ controls basic life functions -​ breathing and heart rate 4.​ Hypothalamus: -​ regulates homeostasis -​ temperature, hunger, thirst 10.​I can explain the reflex arc. A neural pathway that controls a reflex action without conscious brain input steps: 1.​ receptor: detects stimulus ( pain preceptor in skin) 2.​ sensory neuron: transmits signal to spinal cord 3.​ Interneuron: Processes signal in the CNS and sends it to the motor neuron 4.​ Motor Neuron: carries response signal to the effector 5.​ Effector: executes the reflex (muscles contraction to withdraw hand)