Animal responses

• Define the terms "central nervous system", "peripheral nervous system", "somatic nervous system", "autonomic nervous system", "sympathetic nervous system", and "parasympathetic nervous system"

  Central nervous system - consists of the brain and the spinal cordPeripheral nervous system - consists of all the neurones that connect the CNS to the rest of the bodySomatic nervous system - part of the nervous system that is under conscious controlAutonomic nervous system - part of the nervous system that is under subconscious controlSympathetic nervous system - A part of the nervous system that serves to accelerate the heart rate, constrict blood vessels, and raise blood pressure (STRESS)Parasympathetic nervous system - The part of the involuntary nervous system that serves to slow the heart rate, increase intestinal and glandular activity, and relax the sphincter muscles. (PEACE)
• State 4 differences between the autonomic nervous system and the somatic nervous system

  Autonomic not under voluntary control, Somatic under voluntary controlAutonomic mostly non-myelinated or lightly miyelinated, Somatic mostly mayelinatedAutonomic at least 2 neurones to connect CNS with effector, Somatic 1 neurone to connect CNS with effectorAutonomic effectors are cardiac muscle, smooth muscle and glands, Somatic effectors are skeletal muscleAutonomic both parasympathetic and sympathetic motor neurones to same effector, Somatic just somatic motor neurones to each effector
• Define the term "antagonistic system" in relation to the sympathetic and parasympathetic nervous systems, and outline how they co-ordinate responses

  The action of one system opposes the action of the other. Under normal conditions impulses are passing along the neurones of both systems at a relatively low rate. Changes to conditions lead to an altered balance between the two systems which leads to an appropriate response.
• Draw a table to compare the structure and function of the sympathetic and parasympathetic nervous systems.

  Parasympathetic - Rest and digest functions - ganglion within target tissue, uses acetylcholineSympathetic - Fight or flight functions - ganglion just outside spinal cord, uses noradrenaline
• Label a diagram of the human brain showing the location of the cerebrum, cerebellum, medulla oblongata, hypothalamus and pituitary gland

  
• Describe the structure of the cerebrum

  Composed of two hemispheres connected via the corpus callosum. The left hemisphere is connected to the right side of the body and the right hemisphere is connected to the left side of the body. The outermost layer is folded and consists of a thin layer of nerve cell bodies known as the cerebral cortex. The cerebral cortex is subdivided into 4 lobes (frontal, occipital, parietal and temporal) and 3 types of area (association, sensory and motor). These subdivisions overlap considerably.
• Describe the role of sensory areas, association areas and motor areas of the cerebral cortex.

  Sensory - receive impulses indirectly from the receptors (some basic processing)Association - compare input with previoius experiences in order to interpret what the input means and judge an appropriate responseMotor - send impulses to effectors to illicit a reponse.
• Describe the role of the cerebellum in coordinated muscular movement

  Conscious muscle movement decisions from the cerebrum but cerebellum coordinates info from retina, balance organs and spindle fibres to make non-conscious adjustments for fine control. (posture, balance and non-voluntary movement)
• Describe the structure and location of the pituitary gland

  Located at the base of the hypothalamus. It is divided into two sections: the anterior pituitary (which produces hormones involved in growth and reproduction) and the posterior pituitary (which stores and releases hormones made by the hypothalamus such as ADH)
• Draw a table to describe the roles of the cerebrum, cerebellum, medulla oblongata, hypothalamus and pituitary gland (both anterior and posterior).

  Cerebrum - Controls voluntary actions such as learning, memory, personality and conscious thoughtCerebellum - controls unconscious functions such as posture, balance and non-voluntary movementMedulla oblongata - Used in autonomic control, for example, it controls heart rate and breathing rate (also swallowing, peristalsis and coughing)Hypothalamus - Main controlling region for autonomic nervous system. It has two centres - one for sympathetic, one for parasympathetic. Regulating centre for temp. and water balance and controls feeding, sleeping and aggression. Produces hormones.Pituitary gland - stores and releases hormones that regulate many body functions. Anterior - hormones involved in growth and reproduction. Posterior - hormones produced by the hypothalamus such as ADH.
• Define the terms "reflex action", "reflex arc", "stimulus", "receptor", "effector" and "response"

  reflex action - involuntary response to a sensory stimulusreflex arc - the nerve pathway involved in a reflex action, including at its simplest a sensory nerve and a motor nerve with a synapse betweenstimulus - detectable change in external or internal environment of an organismreceptor - an organ or cell able to respond to light, heat, or other external stimulus and transmit a signal to a sensory nerveeffector - muscle or gland which carries out body's response to a stimulusresponse - the way a body reacts to a stimulus
• Draw, label and annotate a diagram to show the arrangement of neurones in the "withdrawal of the hand from a heat stimulus" reflex arc and the actions that occur in the stimulus-response pathway

  Receptor detects stimulus and creates an action potential in the sensory neuroneSensory neurone carries impulse to spinal cordRelay neurone connects the sensory neurone to the motor neurone within the spinal cordMotor neurone carries impulse to the effector to carry out the appropriate response

  
• Describe the characteristics of reflex actions and the survival value of them.

  Responding to situations without conscious thought causes faster responses - can prevent/minimise damage to body. Also prevents brain being overloaded so it is able to deal with more complex decision making. They don't have to be learnt - present at birth providing immediate protection. Most are everyday actions e.g. controlling digestion.
• Draw, label and annotate a diagram to show the arrangement of neurones in the "knee jerk" reflex arc and the actions that occur in the stimulus-response pathway


  When leg tapped just below kneecap (patella), it stretches the patella tendon acting as a stimulus. This initiates reflex arc causing extensor muscle on top of thigh to contract - no relay neurone between sensory neurone and motor neurone which stimulates the extensor muscle. At the same time, relay neurone inhibits motor neurone of flexor muscle causing it to relax.Coordinated antagonistic muscles cause leg to kick.

  
• Explain the "survival value" of the knee jerk reflex

  Helps maintain posture and balance, allowing you to remain balanced with little effort/conscious thought.
• Draw, label and annotate a diagram to show the arrangement of neurones in the "corneal blinking" reflex arc and the actions that occur in the stimulus-response pathway.


  Stimulus: cornea - by touch(lower brain stem, not spinal)Response is consensual - both eyes close in response to stimulus

  
• Describe other stimuli that can trigger the blinking reflex

  Loud noise, bright light
• Explain the "survival value" of the blinking reflex

  Keep cornea safe from damage e.g. dust, flying insectsProtect lens and retina from over bright light
• State the two systems which coordinate mammalian responses to stimuli, and explain why these systems are necessary

  Nervous system, Endocrine systemDifferent types of response - nervous, short term, localised - endocrine, longer term, wide spread
• Define the term "fight or flight response"

  the instinctive physiological response to a threatening situation, which readies one either to resist forcibly or to run away
• Draw a diagram showing how the hypothalamus uses both the nervous system and the endocrine system to coordinate the physiological responses associated with the "fight or flight" response.

  Hypothalamus secretes CRF which stimulates the pituitary gland and triggers the endocrine responseHypothalamus stimulates increased activity in the sympathetic nervous system triggering the nervous response
• Describe the role of the sympathetic nervous system in the "fight or flight" response

  Activates the adrenal medulla which releases noradrenaline and adrenaline.Increases its nerve impulses to effectorsBoth lead to physiological responses
• State the role of corticosteroid releasing factor (CRF) in the "fight or flight" response

  Stimulates the pituitary gland to release ACTH
• State the role of adrenocorticotropic hormone (ACTH) in the "fight or flight" response

  Stimulates the adrenal cortex to release coticosteroid hormones which cause physiological responses
• List 7 physiological changes that occur during the "fight or flight" response and describe the purpose of each

  Pupil dilationIncreased heart rateIncreased blood pressureConstriction of arterioles to skin and digestive systemDilation of arterioles to liver and musclesIncreased blood glucoseIncreased metabolic rateContraction of erector pilli musclesIncreases ventilation rate and depth of breathingRelaxation of smooth muscle in bronchiolesRelease of endorphins in brainIncreased sweat production
• Define the terms "first messenger" and "second messenger"

  First messenger - an extracellular substance (such as the hormone epinephrine or the neurotransmitter serotonin) that binds to a cell-surface receptor and initiates intracellular activitySecond messenger - a substance whose release within a cell is promoted by a hormone and which brings about a response by the cell
• State the two types of hormone and identify which type adrenaline is

  Non-steroid and steroidAdrenaline is non-steroid
• Explain how the properties of the two types of hormone affect the mechanism by which they can influence cells.

  Steroid can diffuse through phospholipid bilayer and bind to receptors inside cellNon-steroid bind to receptors on surface membrane to trigger second messengers within the cell
• Draw a flow chart to show how adrenaline has its effect on cells

  
• Explain why the second messenger system is said to have a "cascade effect", and explain the usefulness of this effect.

  One original molecule can activate many enzymes through a multi-step activation process that allows multiplication of the effect at every stage.
• Suggest how adrenaline can have different effects on different tissue types

  Different enzymes in different cells activated by cAMP.Different second messengerDifferent relationship between receptor and adenylyl cyclase.
• Explain why there is a need to be able to alter heart rate in humans

  Different energy requirements at different times so different amounts of oxygen and glucose required to cells and carbon dioxide removed therefore different rate of blood flow therefore different heart rate.
• Describe two ways in which the heart's action changes in order to supply more oxygen and glucose to cells

  Increased stroke rateIncreased stroke volume
• State 4 factors that are detected by the body which affect heart rate - for each state where they are detected and by what

  Movement of limbs - detected by stretch receptors in musclesBlood pressure - detected by stretch receptors in the walls of the carotid sinus (small swelling in the carotid artery)Carbon dioxide concentration (Blood pH) - detected by chemoreceptors in carotid arteries, aorta and brain.Stress, shock, anticipation or excitement
• Explain why blood pH is a measure of carbon dioxide concentration in the blood

  Carbon dioxide reacts with water in blood to form carbonic acid which lowers blood pH
• State which part of the brain controls heart rate

  Cardiovascular centre in the medulla oblongata
• Name the two nerves that travel from the brain to the SAN, state which centre they come from and state what each does

  Vagus nerve - more frequent impulses slows heart rateAccelerator nerve - more frequent impulses increases heart rate
• Compare the way in which adrenaline concentration in the blood affects heart rate with the way in which carbon dioxide concentration in the blood affects heart rate

  Adrenaline acts directly on heart muscle cells to increase heart rate whereas increased CO2 conc. is detected by chemoreceptors, the information relayed to the cardiovascular centre in the brain which the sends more frequent impulses down the accelerator nerve to increase heart rate.
• Draw a flow chart to show the effect of exercise on cardiac output

  Body's metabolic requirements vary due to intensity of exercise.Movement of limbs detected by stretch receptors in muscles which send impulses to the cardiovascular centre which increases the frequency of impulses down the accelerator nerve which increases heart rate, increasing cardiac output.
• Draw, label and annotate a diagram of a muscle fibre to show the components of the cell and their functions.