C3.1 INTEGRATION OF BODY SYSTEMS

explain system integration in living systems

the human body is a collection of system which has interacting and interdependent parts that create emergent properties, both of which require coordination from the nervous or endocrine system

using cheetas as an example, explain how its system intergration and emergent properties make it an effective preadator

• large hearts, arteries, lungs, adrenal glands and muscles coordinated by the nervous and endocrine systems make it an effective predator

explain cells, tissues, organs and body systems as a hierarchy of subsystems that are integrated in a multicellular living organism

• emergent properties rise when individual components produce new functionalities

  • cells: basic unit of life

  • tissues: same type of cells grouped together

  • organs: functional grouping of tissues composed of the same cell types

  • systems: organs interacting to carry body functions

  • organisms: organ systems collectively carrying out life functions

• this integration is responsible for emergent properties

outline the pathway of the nervous system and also how they detect stimuli

• receptor cells detect stimuli which sends signals using sensory neurons to the central nervous system

• stimuli → receptors → sensory neurons → spinal chord OR brain (CNS) → motor neurons → effectors → responses

  • sensory neurons : sends signals from receptors to the CNS which consist of the brain and spinal chord

    • the spinal chord coordinates unconscious responses such as reflexes and conveys signals to and from the brain

    • the brain coordinates and processes both conscious and unconscious information, receiving complex sensory inputs that facilitate learning and memory formation

  • motor neurons: brings signals from the CNS to effectors

explain how the brain controls motor functions

• left and right cerebral hemispheres control muscle via motor neurons which causes them to contract as a response

• left cerebral hemisphere controls right side of body functions

• right cerebral hemisphere controls left side of body functions

outline the function of the cerebellum

• receives input from cerebral hemisphere

• involved in motor learning

• coordinates contraction of skeletal muscles

  • overall control of body movement such as precision and timing of movement

    • eg) coordinates walking, running, balance, posture

outline the structure and function of nerves

• nerves are bundles of axons of neurons

  • 2 types: sensory and motor neurons

  • they can be myelinated or unmyelinated

• nerve fibers are bundled together inside protective sheaths of connective tissue

describe a pain reflex arc

• it is an involuntary response

  • painful stimulus is detected by free nerve endings known as sensory neurons which transmit pain signals to the spinal chord, a part of the central nervous system

  • the sensory neuron synapses with an interneuron in the grey matter of the spinal chord, allowing for the interneuron to process the information and relay the signal to motor neurons

  • the interneuron activates a motor neuron which synapses with the effect, a skeletal muscle causing an involuntary contraction to withdraw from the painful stimulus

explain the integration of organs in animal bodies by hormonal and nervous signalling and by transport of materials and energy

• communications within animal bodies between body organs consist of the endocrine and nervous system

  • endocrine system: made up of ductless endocrine glands releasing chemical messengers (hormones) into the blood stream

    • the hypothalamus and CNS controls the endocrine system using a nrual and hormonal conncection to the pituitary gland which secretes hormones

      • act on distant target cells, wider distribution, longer duration effect

  • nervous system: network of neurons transmitting electrochemical impulses

    • act on localised target, short duration effect

explain how peristalsis is coordinated by the CNS and ENS

• coordinated contraction and relaxation of

  smooth muscle in the digestive tract that moves

  materials through the digestive system

  • swallowing and egestion of feces is a voluntarily controlled by the central nervous system

  • peristalsis from esophagus to rectum is an involuntary coordination controlled by the enteric nervous system which consists of nerves from the esophagus to the rectum

    • its functions independently from the CNS

describe the process of negative and positive feedback

negative feedback:

• if output increases, the system reacts to decrease it

• used in homeostasis to regulate/maintain conditions within set limits

positive feedback:

• if output increases, system reacts to increase it

• increase of an output causes an even greater increase in the output

explain the role of the medulla in coordinating responses and sending nerve impulses to control the feedback of heart rate

• medulla oblongata is a part of the brainstem which regulates the cardiovascular and respiratory systems via nerve impulses

  • can increase and decrease heart rate and ventilation rate based on sensory input from baroreceptors and chemoreceptors

    • located in the carotid arteries and the aorta

• baroreceptors monitor blood pressure

• chemoreceptors monitor blood pH, oxygen and carbon dioxide concentrations

using baroreceptors and chemoreceptors as an example, outline how relates to chemical feedback

• baroreceptors: aka stretch receptors which are cells that detect the changes in circumference of arteries

  • baroreceptors signal the medulla and the medulla decreases heart rate and stroke volume and dilates blood vessels

• chemoreceptors: cells that detect concentrations of oxygen, carbon dioxide and blood pH

  • increased cell respiration increases CO2 conc, decreases O2 and pH conc which is detected by chemoreceptors, signalling the medulla

  • the medulla recieves the signal and sends a signal to the heart to increase heart rate to increase ventilation rate

outline the role of adrenaline secretion and how this helps facilitate intense muscle contraction

• the hormone adrenaline is released from adrenal glands in response to stress, triggering the fight or flight response

• this can affect various organs as it prepares it for vigorous activities with intense muscle contractions which is done by

  • increasing heart rate and blood pressure

  • increase in ventilation rate

  • increases blood glucose levels and fatty acid concentrations

explain how the cycle of sleeping and waking is established by a diurnal pattern of melatonin secretion

• presence of light is detected by photoreceptors which send signals to the optic nerve to signal the pineal gland to either decrease or increase melatonin

  • light = dec melatonin

  • dark = inc melatonin

    • increase in melatonin is caused by decrease in body temperature and brain activity

• the circadian rhythm is a diurnal (daily) pattern of melatonin secretion by the pineal gland

  • a 24 hour pattern of physiological changes, mainly affected by the light and dark cycle