Higher Human Biology

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

2. Reminder from N5 Biology! Discuss these questions with a study buddy or your group • 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?

3. Higher Human Biology We are going to build on the knowledge and skills that you developed during N5 and will learn about the following Neurobiology key areas : - Key Area 1A - Divisions of the nervous system & neural pathways Key Area 2A – The Cerebral Cortex Key Area 3A - Memory Key Area 4A - The Cells of the nervous system and neurotransmitters at synapses

4. Neurobiology & Communication Learning Intentions KEY AREA 1A - 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

5. 1a) 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

6. 1b) Structure & function-Central Nervous System (CNS) CNS Nerve impulses carried by sensory neurons in sensory pathways Nerve impulses carried by motor neurons in motor pathways receptors effectors responses stimuli

7. 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 1c) Peripheral Nervous System (PNS)

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

9. Antagonistic Methods of the Sympathetic and Parasympathetic System in response to a stranger chasing you! 1e) Autonomic Nervous System- Sympathetic & Parasympathetic

10. 1f) Autonomic Nervous System - antagonistic nature

11. 1g) Autonomic Nervous System Sympathetic & Parasympathetic balance each other – body rarely at extremes

12. 1h) 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

13. 1i) 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

14. 1j) 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

15. 1k) 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)

16. 1l) 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

17. Neurobiology Questions KEY AREA 1A - Divisions of the nervous system & neural pathways • Testing Your Knowledge 1 Page 208 Q’s 1-4 • Testing your Knowledge 2 Page 264 Q1 only • What you should know Page 219 Q1-6 • What you should know page 277 Q 10-12 5. Quick Quiz