Higher Human Biology Unit 3 A Neurobiology KEY

Higher Human Biology Unit 3 A Neurobiology KEY AREA 1 A: Divisions of the Nervous System & neural pathways

Reminder from N 5 Biology! Discuss these questions with a study buddy or your group 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. What is the nervous system? What is the CNS? What are the 3 main parts of the brain? What is a reflex action? What makes up the reflex arc? What is a synapse? What is the Endocrine System? What are Hormones? Where do Hormones have an effect? What is Homeostasis?

Higher Human Biology We are going to build on the knowledge and skills that you developed during N 5 and will learn about the following Neurobiology key areas : - Key Area 1 A - Divisions of the nervous system & neural pathways Key Area 2 A – The Cerebral Cortex Key Area 3 A - Memory Key Area 4 A - The Cells of the nervous system and neurotransmitters at synapses

Neurobiology & Communication Learning Intentions KEY AREA 1 A - Divisions of the nervous system & neural pathways a) Structure & function of the Central Nervous System (CNS) b) Structure & function of the Peripheral Nervous System (PNS) c) Autonomic Nervous system- Sympathetic & Parasympathetic Nervous Systems d) Fight or Flight & Rest and Digest e) Structure and function of converging, diverging & reverberating neural pathways

1 a) Structure & function- Central Nervous System (CNS) The nervous system is made up of the: Brain Spinal Cord Nerves Sense Organs Structural division of the nervous system: Central Nervous System (CNS) (Brain & Spinal cord) Peripheral Nervous System (PNS) (Nerves) Peripheral nerves contain a sensory pathway made of sensory nerves and a motor pathway made of motor nerves Sensory pathways carry nerve impulses from sense organs (e. g. skin) to the CNS The CNS analyses the information and sends nerve impulses along motor pathways to effectors (e. g. muscles/glands) which then bring about a response e. g. muscle contraction/secretions from endocrine glands

1 b) Structure & function-Central Nervous System (CNS) CNS Nerve impulses carried by sensory neurons in sensory pathways receptors stimuli Nerve impulses carried by motor neurons in motor pathways effectors responses

1 c) Peripheral Nervous System (PNS) The peripheral nervous system is made up of the Somatic Nervous System and the Autonomic Nervous System (ANS) SNS contains sensory and motor neurons which control the voluntary movement of skeletal muscles SNS brings about some involuntary actions (e. g. reflex response) but majority of actions are under voluntary control (e. g. picking 4 favourite chocolates out a large box of chocolates) ANS regulates the internal environment by controlling structures and organs (e. g. heart, blood vessels, bronchioles) This control is involuntary because it works automatically without the person’s conscious control being involved The sympathetic and parasympathetic systems of the ANS are antagonistic, meaning that they affect many of the same structures but in opposite ways in order to maintain a stable internal environment

1 d) Central Nervous System (CNS) & Peripheral Nervous System (PNS) Divisions of the Nervous System Structural & Location Division Functional Division

1 e) Autonomic Nervous System- Sympathetic & Parasympathetic Antagonistic Methods of the Sympathetic and Parasympathetic System in response to a stranger chasing you! Sympathetic System Parasympathetic System Type of response “fight or flight” “rest and digest” Response occurs At start of event when sensory nerves stimulated At end of event when excitement is over Heart Rate Increases Return to normal Blood Pressure Increases Return to normal Blood supply Increased supply at muscles Decreased supply at gut/skin Return to normal Peristalsis increases Nervous perspiration Increases Return to normal Characteristics Thudding heart White face with fear Clammy armpits and hands Return to normal Adrenaline(epinephrine) Produced Not produced Response Return to normal to help body conserve resources and store energy Fight or run away!

1 f) Autonomic Nervous System - antagonistic nature

1 g) Autonomic Nervous System Sympathetic & Parasympathetic balance each other – body rarely at extremes

1 h) Fight or Flight ‘Fight or flight’ – sympathetic nervous system sends more impulses than the parasympathetic in order to prepare the body to use energy quickly Heart rate and breathing rate increase peristalsis and production of intestinal secretions decrease blood pressure increase and blood supply diverted to skeletal muscles After the ‘fight or flight’ situation has passed the parasympathetic nervous system takes over briefly to calm you down

1 i) Rest and digest After the ‘fight or flight’ situation has passed the parasympathetic nervous system takes over briefly to calm you down Heart rate and breathing rate drop Rate of peristaltic contractions & production of intestinal secretions increase Blood re-diverted back to intestines NOTE: Fight or Flight and Rest and digest involve many neurons interacting in several different pathways

1 j) Structure and function of Converging neural pathways Converging • Impulses from several neurons travel to one neuron (concentrating impulses) • Example: Rods & Cones in eye • This increases the sensitivity to excitatory or inhibitory signals

1 k) Structure and function of diverging neural pathways Diverging • Impulses from one neuron travel to several neurons • affecting more than one destination at the same time • Example: Temperature control – muscles, arterioles, sweat glands)

1 l) Structure and function of reverberating neural pathways Reverberating • Neurons later in the pathway link with earlier neurons • sending the impulse back through the pathway (this allows repeated stimulation) • Example: breathing

Neurobiology Questions KEY AREA 1 A - Divisions of the nervous system & neural pathways 1. 2. 3. 4. 5. Testing Your Knowledge 1 Testing your Knowledge 2 What you should know Quick Quiz Page 208 Page 264 Page 219 page 277 Q’s 1 -4 Q 1 only Q 1 -6 Q 10 -12