Coordination in mammals title Coordination in mammals

16.2 Neurones as the basic units of the nervous system content Coordination in mammals 16.1 The nervous system 16.2 Neurones as the basic units of the nervous system 16.3 Nervous coordination 16.4 The structure and functions of the brain 16.5 The structure and functions of the spinal cord 16.6 What is a reflex action? 16.7 Hormonal coordination 16.8 Examples of hormones

16.1 The nervous system Nervous system peripheral nervous system (PNS) cranial nerve brain central nervous system (CNS) spinal cord spinal nerve Nervous system coordinates the receptors and effectors consists of two parts The human nervous system

16.2 Neurones as the basic units of the nervous system nerve cells Neurones basic units of the nervous system transmit nerve impulses

speeds up the transmission of nerve impulses The structure of neurones Neurone cell body nerve fibres axons dendrons conduct nerve impulses away from the cell body surrounded by myelin sheath conduct nerve impulses towards the cell body speeds up the transmission of nerve impulses protects axons

Nerves The structure of neurones nerve fibres of many neurones wrapped in connective tissue a nerve fibre (axon or dendron) a bundle of nerve fibres connective tissue The make-up of a nerve

1 Sensory neurone Three types of neurones receptors CNS in CNS axon impulses receptors CNS cell body dendron receptor

2 Intermediate / Association neurone Three types of neurones 2 Intermediate / Association neurone sensory neurone cell body motor neurone impulses in CNS dendron axon

3 Motor neurone Three types of neurones CNS effector in CNS cell body impulses CNS effector axon effector

chemicals released from ending diffuse across the synapse How are nerve impulses transmitted across neurones? neurones are separated by synapses synapses enable nerve impulses to travel in one direction only ending of axon chemicals released from ending diffuse across the synapse synapse dendron

Examination of neurones from a slide or a model Carry out Practical 16.1 Examination of neurones from a slide or a model

16.3 Nervous coordination CNS PNS receptor receives stimuli and generates nerve impulses stimuli receptors impulses are transmitted to CNS via sensory neurones sensory neurone intermediate neurone motor neurone effector

16.3 Nervous coordination CNS PNS brain spinal cord receptors information is processed and integrated in CNS which then generates nerve impulses sensory neurone intermediate neurone motor neurone effector

16.3 Nervous coordination CNS PNS impulses are transmitted via motor neurones to the effector receptors sensory neurone effector brings about a response intermediate neurone motor neurone response effector

16.4 The structure and functions of the brain The protective structures: cranium 3 layers of membranes central cavity filled with cerebrospinal fluid absorbs shock provides brain with nutrients and O2 removes wastes from brain cells maintains shape of brain

16.4 The structure and functions of the brain The 3 main parts: cerebrum cerebellum medulla oblongata

The cerebrum site of intelligence and controls voluntary actions outer layer: grey matter/ cerebral cortex (cell bodies of motor and intermediate neurones) inner layer: white matter (axons and dendrons of neurones)

The cerebrum consists of 2 halves: left cerebral hemisphere controls movement of right side of the body right cerebral hemisphere controls movement of left side of the body the 2 halves are connected by nerves for communication

The 3 main areas in the cerebral cortex The cerebrum The 3 main areas in the cerebral cortex Sensory areas receive impulses from various receptors Association areas link information from different sensory areas/receptors Motor areas send out impulses to effectors

The cerebellum coordinates and controls muscular movements maintains balance outer layer: grey matter inner layer: white matter cerebellum

reverse of that in cerebrum and cerebellum The medulla oblongata controls reflex actions and involuntary actions outer layer: white matter inner layer: grey matter reverse of that in cerebrum and cerebellum medulla oblongata

Examination of a mammalian brain or a brain model Carry out Practical 16.2 Examination of a mammalian brain or a brain model

16.5 The structure and functions of the spinal cord The protective structures central canal filled with cerebrospinal fluid spinal cord 3 layers of membranes vertebral column

a thick bundle of nerves and neurones Spinal cord a thick bundle of nerves and neurones outer layer (white matter) inner layer (grey matter) dorsal root (sensory neurones) ventral root (motor neurones) dorsal root ganglion (cell bodies of sensory neurones) spinal nerve

The functions of the spinal cord relays nerve impulses between the brain and other body parts responsible for reflex actions brain nerve impulses enter and leave the brain through the spinal cord spinal cord

16.6 What is a reflex action? stereotyped response inborn rapid unconscious is reflex action can be cranial reflex spinal reflex brought about by brought about by impulses travelling through the brain impulses travelling through the spinal cord

Reflex arc the nervous pathway between a receptor and an effector which brings about a reflex action sensory neurone receptor intermediate neurone (may be absent) motor neurone effector

Examples of reflex actions Withdrawal reflex Knee jerk reflex

Differences between reflex actions and voluntary actions involve cerebrum? No Yes involve receptor ? Yes Not necessarily No, they are learnt inborn? Yes

Differences between reflex actions and voluntary actions under conscious control? No Yes speed of response Faster Slower response to same stimulus Various responses Stereotyped response

16.7 Hormonal coordination Hormones chemicals secreted by ductless endocrine glands transported in blood act on target organs and regulate body processes blood capillary endocrine gland diffusion of hormones to the blood

Ovaries (females) Testes (males) Pituitary gland Endocrine glands Ovaries (females) Testes (males) Pituitary gland Adrenal glands Thyroid gland Pancreas Endocrine system responsible for coordination by hormones

How do hormones coordinate differently from nerves? Nervous coordination Hormonal coordination Components Types of message Transmission route Neurones, brain & spinal cord Endocrine glands & blood Nerve impulses Hormones Nerve fibres Blood stream

How do hormones coordinate differently from nerves? Nervous coordination Hormonal coordination Response occurs Speed of transmission Duration of response Only in places with nerve supply In more widespread area Rapid Slower Short-lived Usually long lasting

similar to the operation of a thermostat in an air-conditioner 16.8 Examples of hormones Insulin produced in pancreas regulates blood glucose level by a negative feedback mechanism similar to the operation of a thermostat in an air-conditioner

Normal blood glucose level Insulin More insulin is secreted (1) more glucose is converted to glycogen in liver (2) more glucose is oxidized to CO2 and H2O in body cells High blood glucose level Blood glucose level falls Normal blood glucose level Less insulin is secreted (1) more glycogen in liver is converted to glucose (2) less glucose is oxidized in body cells Low blood glucose level Blood glucose level rises

produced in ovaries (female) and testes (male) Sex hormones produced in ovaries (female) and testes (male) production increases tremendously during puberty the time when boys and girls become sexually mature testes begin to make sperms ovaries begin to release eggs responsible for the development of secondary sexual characteristics

secondary sexual characteristics of male include Sex hormones secondary sexual characteristics of male include BOYS AT PUBERTY hair growing on the face, armpits and around the genital area the larynx enlarges and the voice deepens the penis and testes grow larger the shoulders broaden, the body becomes more muscular

characteristic figure of Sex hormones secondary sexual characteristics of female include GIRLS AT PUBERTY hair starts growing on the armpits and around the genital area more fat deposits on the body & beneath the skin the breasts develop the hips broaden, giving the characteristic figure of the female body

Coordination in mammals Concept diagram Coordination in mammals discuss later is achieved by consists of nervous system neurones organized into

Concept diagram nervous system central nervous system organized into nervous system central nervous system peripheral nervous system consists of

Concept diagram central nervous system brain spinal cord consists of transmits impulses to and from brain spinal cord involved in involuntary responses including reflex arcs reflex actions involving

Concept diagram brain cerebrum cerebellum medulla oblongata mainly consists of cerebrum cerebellum medulla oblongata controls controls controls maintains involuntary actions voluntary responses muscle coordination balance

Concept diagram nervous system central nervous system organized into nervous system consists of central nervous system peripheral nervous system neurones consists of each consists of cranial nerves spinal nerves made up of each made of many nerves nerve fibres cell body classified into axons dendrons

Concept diagram neurones sensory neurones intermediate neurones classified into neurones carry messages in the form of sensory neurones intermediate neurones motor neurones receive messages from send messages to nerve impulses receptors effectors on receiving carry out stimuli from environment responses

Concept diagram Coordination in mammals discussed endocrine glands is achieved by endocrine glands consists of endocrine system produce chemical messengers called negative feedback mechanism hormones carry messages through blood to many actions regulated by effectors carry out responses