C3.1 Integration of body systems

Emergent property

exist when the sum of all parts creates a feature that does not exist withing individual components

Autonomic nervous system

unconscious

Nervous system features

• electrical impluses send messages

• both involontary and volontray actions

• trasmiy by neurons

• repsone quick but short lived

Endocrine system features

• only involonutray actions

• hormones are messangers

• travel in blood stream

• longer to work but long lived

Integration of endocrine and nervous system eg. epinephrine

• sensory neurone inidcated that epinephrine is needed

• autonic nervous system send action potential to adrenal galnds

• those relase epineprhine in the bloodstream

• leading to incresed heart rate and blood flow

osmoreceptors

sense solutes and water content in blood

baroreceptors

sense blood pressure

thermoreceptors

in skin sense temprature

photoreceptors

sense visual info in retina

chemoreceptors

in tounge for tasting

somatic nervous system

volountray movements

Role of brain

processing information, memory and learning

cerebrum

separted into two cerebral hemispehres whihc are seprated into 4 lobes: frontal, temporal, parietal and occipital → all involved in conscious activities

Cerebellum

volontray movemsnts, balance and equilibrium

Brainstem

• involounray

• and passing info between cerebrum or cerebellum and spinal cord

• consists medulla ooblongata which regulates breathing and heart rate

Spinal cord role

• passes information to the brain

• also involountrayt behaviour including balance and reflex arc

White matter in spinal cord

• goes to the brain

Grey matter in spinal cord

Does not pass to the brain → reflex arc

Transcution

conversion of a physical stimulus into an action potential

acteylcoline

initiates contraction of sarcometres

motor neruons

responsible for synapses with muscle fibres

Interneurons

located between sensory and motor neurone onyl found in CNS

Mixed nerves

both motor and sensory neurons

Pain reflex arc

1. Nocireceptor initiates afferenet (sensory) action potemtial

2. The action potential travels to spinal cord in the grey matter

3. synapses with an interneuron in the grey matter

4. interenuorn synapses with motor neuron

5. action potentail travels to effectr (muscle)

Motor cortex

initiates muscle contractions

Cerebellum role (does not initiate movement)

Cerebellum receivses impulses when body begins to move and sends back action potentail to coordinate that movement

Melatonin

• pineal gland - between cerebrum and brainstem

• regulates sleep schedule

• when dark melatonin secreted

• when light not

• regulates whether u feel tires

circadian rhythm

pattern of bhaviour or physiology that is based on a 24 hour cycle

Effect of epinephrine on the body

• increased heart rate and blod pressure

• increased breathing arte

• dilation of pupils

• increased blood supply to muscles

• increased blood sugar

hypothalamus

• link between endocrine and nervous system

• connected to pituitary

• Sends hormone to anterior pituitaory

• sends action potential to posterior pituiatory

ADH

• produced by hypothlamus sent to posterior

• HYpothalmaus sends ADH via neurons to the posterior where they are secreted

• Osmoreceptor near hypothalmus detect water content of blood if its too low ADH will be secretd to collecting tubules of nephrons

• This will cause reabsortio fo water that was supposed to be relased in urine

• example of negative feedback

Control of heart rate

• barorecpetors on aorta and carotid sinus sense increased blood pressure send an action potential to medulla oblongata which sends an action potential to SA node to decrease heart rate and force of contraction

• chemoreceptors sense CO2, O2 levels and pH - with increased cell repisration baroreceptor sense that sending impulse to medulla oblongata which sends action potential to SA node

Control of ventilation rate

• respiratory centres in medulla

• chemoreceptors in medulla sense bloood pH and CO2 content

• normla blood pH 7.35-7.45

• During exercise more CO2 will be produced

• Chemorreptors will send signal to medulla which will sned signal to lungs to increase ventialtion rate and increase the amount of air isnpired

Control of peristalsis

• Enteric nervous system

• movement of bolus in alimentray canal

• When bolus in area it becomes swollen. receptors sense that synapse with interneuron which synapses with tow motor neuornes. one relases excitaory neurotramsitter to teh arae behind pushing blous forward and the othe r an inhibiptyr neuortramsitter causing relaxation of the area where bolus will go.

• This happens multiple times

Phototropism

growing towards a source of ligh

Phytohormones

hormones produced by plants

auxin function

plant cell elongation

cytokinin function

increased rate of cell division

ethylene function

promotes fruit rippening

gibberellin function

control stem elongation, seed germination, floweirng and dormancy

auxin travels in plant by

phloem

how does auxin enter cells

auxin efflux carriers

Plant cell elongation process

1. Auxin promotes synthesis of hydrogen ions pump and stimulates their insertion into the plasma membrane

2. Protons using ATP move into the apoplast

3. Hydrogen ions activate a protein - expansin

4. Expansin loosens hydrogen bonds between cellulose fibres allowing them to move into new positions

5. High internal turgor pressure generates the force for fibres to slide past each other

6. cellulose fibres make new hydrogen bonds in their new positions

Where is auxin produced

shoot

Where is auxin used

root

Where is cytokinin produced

root

Where is cytokinin used

shoot

How does cytokinin travel

xylem

Fruit ripening

When a fruit ripens it relases ethylene causing a positive feeback loop as this triggers other fruit to strat ripening