Higher Human Biology

Unit 3 Neurobiology & Communication

KEY AREA 1: Divisions of the Nervous System & parts of the brain

Reminder from N5 Biology!Discuss these questions with a study buddy or your group

1.What is the nervous system?2.What is the CNS?3.What are the 3 main parts of the brain?4.What is a reflex action?5.What makes up the reflex arc?6.What is a synapse?7.What is the Endocrine System?8.What are Hormones?9.Where do Hormones have an effect?10.What is Homeostasis?11.Why is it important that our Glucose, Water & Body Temperature are controlled?12. Which parts of our brain help to control blood water concentration and temperature?

Higher Human BiologyWe 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 1 - Divisions of the nervous system & parts of the brain

Key Area 2 - Perception and memory

Key Area 3 - The cells of the nervous system and neurotransmitters at synapses

Key Area 4 - Communication and social behaviour

Neurobiology & Communication Learning IntentionsKEY AREA 1 - Divisions of the nervous system & parts of the brain

a) Structure & function of the Central Nervous System (CNS)

b) Structure & function of the Peripheral Nervous System (PNS) and the Somatic Nervous System (SNS)

c) Functions of the medulla and cerebellum in the central core of the brain

d) Functions of the limbic system

e) Functions of the cerebral cortex in receiving information, coordinating voluntary movement and making decisions in light of experience

f) Localisation of brain functions including sensory and motor areas and association areas

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 sensorynerves and a motor pathway made of motor nerves

Sensory pathways carry nerve impulses from receptors (e.g. skin) to the CNS

The brain analyses the information and sends nerve impulses along motor pathways to effectors (e.g. muscles) which then bring about a response e.g. muscle contraction

1b) Structure & function-Central Nervous System (CNS)

responses

receptors effectors

Nerve impulses carried by sensory neurons in sensory pathways

Nerve impulses carried by motor neurons in motor pathways

CNS

stimuli

1c) Peripheral Nervous System(PNS) & SomaticNervous System(SNS)

Somatic Nervous System (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)

Autonomic Nervous System (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

1d) Peripheral Nervous System(PNS) & Somatic Nervous System(SNS)

Divisions of the Nervous System

Structural & Location Division Functional Division

1e) Peripheral Nervous System(PNS) & Somatic Nervous System(SNS)Antagonistic Methods of the Sympathetic and Parasympathetic System in response to a man chasing you!  Sympathetic System Parasympathetic SystemType of response “fight or flight” “rest and digest”Response occurs At start of event when sensory

nerves stimulatedAt end of event when excitement is over

Heart Rate Increases Return to normalBlood Pressure Increases Return to normalBlood supply Increased supply at muscles

Decreased supply at gut/skinReturn to normalPeristalsis increases

Nervous perspiration

Increases Return to normal

Characteristics Thudding heartWhite face with fearClammy armpits and hands

Return to normal

Adrenaline(epinephrine)

Produced Not produced

Response Fight or run away! Return to normal to help body conserve resources and store energy

1f) Autonomic Nervous System - antagonistic nature

1g) Peripheral Nervous System(PNS) & Somatic Nervous System(SNS)Sympathetic & Parasympathetic balance each other – body rarely at extremes

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 quicklyHeart rate and blood pressure increase and blood supply diverted to skeletal musclesNervous perspiration increasesEpinephrine production stimulatedAfter the ‘fight or flight’ situation has passed the parasympathetic nervous system takes over briefly to calm you down

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 blood pressure drop

Rate of peristaltic contractions increase

Blood re-diverted back to intestines

1j) The BrainThe brain is composed of 3 interconnected layers : -The central core - Medulla(breathing, heart rate ) &Cerebellum (balance, coordination, posture)The limbic system - HypothalamusThe cerebral cortex - Outer layer of the cerebrum

1k) Functions of the Limbic System

The limbic system is found in the cerebral cortex

The function of the limbic system is to:-Process information to form long-term memoriesRegulate emotions (e.g. anxiety, fear, aggression)Influence biological motivation (e.g. hunger, thirst, sex drive)

The limbic system contains the hypothalamus

The hypothalamus is connected to the pituitary gland, and acts as a link between the nervous system and the hormonal (endocrine) system

1l) Functions of the Cerebral CortexThe cerebral cortex is the centre of conscious thought; it also recalls memories and alters behaviour in light of experience

The cerebral cortex is the outer layer of the cerebrum and is split into two halves called the cerebral hemispheres.

The left hemisphere processes information from the right visual field and controls the right side of the body

The right hemisphere processes information from the left visual field and controls the left side of the body

The left and right hemispheres are connected by a large bundle of nerve fibres called the corpus callosum. The corpus callosum transfers information between the two hemispheres

1m) Localisation of Brain Function

The cerebral cortex is the centre for conscious thought and contains 3 types of localised functional areas: -Sensory (receives sensory impulses from receptors e.g. skin)Association (analyses, interprets & take decisions)Motor (sends motor impulses to muscles e.g. move hand)

Each cerebral hemisphere consists of distinct areas which have a particular function to perform e.g. speech motor area, auditory area, visual area

Interconnections between each area occur due to tiny nerve fibres. This allows for sophisticated perception of a situation and the ability to make an integrated response.

There are areas of the cerebral cortex that are responsible for higher mental processes such language, personality, imagination, creativity, conscience and intelligence

Neurobiology & Communication QuestionsKEY AREA 1 - Divisions of the nervous system & parts of the brain

1.Testing Your Knowledge 1 Page 208 Q’s 1-4

2. Testing Your Knowledge 2 Page 219 Q’s 1-3

3.What you should know Page 219 Q1-12

4. Quick Quiz