Transcript File
Biology Control & Communication: Nervous & Hormonal Control Nervous System Endocrine System Learning Intentions 1. What is the nervous system? 2. What is the CNS? 3. What are the 3 main parts of the brain? 4. a) What is a reflex action? b) What makes up the reflex arc? c) What is a synapse? 1. What is the Nervous System? The nervous system is made up of the:- Brain Spinal Cord Nerves Sense Organs 2. What is the CNS? The central nervous system (CNS) is made up of the:Brain Spinal Cord Nerves carry information from the senses to the CNS and from the CNS to the muscles The job of the CNS is to sort out information from the senses and send information to the muscles so they make a response. 3. Parts of the Brain Part Function Cerebrum control thought, memory, emotions, personality Cerebellum control balance and co-ordination Medulla control some automatic responses such as heart rate, breathing, peristalsis 4a) Reflex Action The nervous system is made up of cells called neurons There are 3 basic types of neurons Sensory Neurones Relay Neurones Motor Neurones A Reflex Action in an involuntary response to a stimulus to avoid harm SENSORY NEURONES detect the hot stimulus & send electrical impulses to the RELAY NEURONES in the spinal cord Relay Neurone Sensory Neurone RELAY NEURONES send electrical impulses to the MOTOR NEURONES, which make the muscles move Relay Neurone Motor Neurone 4b) Reflex Arc Sense organs contain sensory neurones which carry information (via electrical impulses) from receptors to the CNS Relay neurones are found in the CNS and transfer information (via electrical impulses) from sensory neurones to motor neurones Motor neurones transfer information (via electrical impulses) from the relay neurone to the muscles 4c) Reflex Response Describe the steps involved in the following REFLEX ACTIONS Remember to use the SENSORY NEURONE, RELAY NEURONE, MOTOR NEURONE Hammer on Knee Cap Touching hot plate Sneezing due to dust 4d) Synapse Axon (End of Sac of chemical Neurone) transmitter Two neurones meet at a gap called a synapse. Chemical transmitters are released into the synapse from the leading neurone which allows an electrical impulse to be transferred to the next neurone Receptors Learning Intentions 5. What is the Endocrine System? 6. a)What are Hormones? b)Where do Hormones have an effect? 7. a) What is Homeostasis? Why is it important that our Glucose, Water & Body Temperature are controlled? b) & c) Describe Blood Glucose Control 8. Diabetes 5.What is the Endocrine System? The Endocrine System is made up of endocrine glands which secrete hormones into the bloodstream. 6a) What are Hormones? Hormones are chemical messengers produced at one site and have their effect at another site Hormones are proteins that act as chemical messengers Endocrine Gland Hormone Effect Pituitary Gland in the brain Human Growth Hormone Stimulates growth of long bones Pituitary Gland in the brain Anti-diuretic Hormone Controls water reabsorption in the kidneys Islets of Langerhans in the Pancreas Insulin Controls conversion of excess glucose in the liver 6b) Where do Hormones have an effect? Hormones travel in the blood to their Target Tissues. Target tissues have specific receptors for particular hormones, so when the hormone reaches the target tissue it stimulates an effect. Non- Target tissues don’t have specific receptors for the hormones so they remain unaffected 6c) Differences between Messages Feature Messages via Hormones Messages via Nerves How is the information passed on? Chemicals Electrical Impulses How is the message carried Blood around the body? Nerves How long does the message last? Short lasting Long lasting 7a) What is Homeostasis? Homeostasis is the control of the internal environment in the body Homeostasis is important so that body cells can function properly Homeostasis controls water concentration in the blood (osmoregulation). This prevents cells from bursting or shrinking due to osmosis Homeostasis controls body temperature (thermoregulation). This ensures enzymes are working at an optimum temperature Homeostasis controls glucose concentration in the blood. This ensures that cells receive the correct levels of glucose required for respiration 7b) Homeostasis & Blood Glucose Levels 7c) Controlling Blood Glucose Levels The pancreas monitors the concentration of glucose in the blood Receptor cells in the pancreas detect changes in blood glucose concentration When blood glucose INCREASES - pancreas releases the hormone insulin - insulin travels in the blood to the liver - liver then converts the glucose to glycogen (an insoluble storage carbohydrate) - blood glucose concentration decreases When blood glucose DECREASES - pancreas releases the hormone glucagon - glucagon travels in the blood to the liver - liver converts glycogen to glucose - blood glucose concentration increases 8. Diabetes Diabetes is a disease caused by a failure to control blood glucose concentration. There are 2 types of Diabetes Diabetes Type Communication pathway problem Thought to be caused by Treatment Type 1 Diabetes Pancreatic cells can no longer make insulin Genetics Environmental Factors Autoimmune Factors Insulin injections Insulin pump Careful diet Type 2 Diabetes Target tissues do not respond to insulin Unhealthy diet leading to obesity Physical Inactivity Genetics Exercise Weight loss Diet Control Sometimes insulin