C3.1 Integration of body systems

System integration

• All org - use multiple systems → perform various fun of life

  • Requires coordination of diff systems via comm (chem + electrical)

• Ex. Nervous, cardiovascular, respiratory, etc. system

Hierarchy of body systems

• Cell → smallest unit of life

  • Grouped tgt → form tissue 

• Tissue

  • Similar cells carry out specific func

  • Grouped tgt → organ

• Organs → tissues work tgt → carry out specifc body func

  • Tgt → form body sytem

• Body system → Diff organs work tgt

• Organism

  • made of interconnected + interdependent body systems → carry out func of life

Emergent property

Multic org → capable of completing func 

• Char of system → arise from interaction btwn indiv components

• not present in components themselves

Ex.

• tissues have properties cells do not

• Organs have properties tissue don’t

Ex. Cheetah

Cell - Provide blueprint for body shape and fur - create spots for camo

Tissue - loose hips + shoulder joints → flexible spint for running 

Organ - enlarged heart → ensure effective deliverly of glucose and o2 to muscle for rapid physical respone

Body system → respiratory system → rapid delivery of o2 to muscle, etc.

Organism → built for chasing prey. narrow paws → minimal contact w ground (run faster)

Nervous vs endocrine system. Role of blood in transport of material + e btwn organs

Refer to photo

Transport of materials and e

• blood

  • transport nutrients, o2, etc. (o2 required for cellular respiration in cells)

  • remove waste product (co2, urea)

• Flow maintained by circulatory system + pumping of blood

Nervous system

• Complex network - control + coor body actions + sensory info

• CNS

  • Brain

  • Spinal cord

• PNS

  • Neuron - relay signal btwn CNS + organs of body

    • Ex. Sensory, motor neuron

  • Somatic (voluntary) or autonomic (involuntary)

• Autonomic output

  • Sympathetic (Fight or flight)

    • Mobolise body for action

  • Parasympathetic (rest and diegest)

    • Promote e conservation

Brain

Central info of integration organ

• Function

  • Receive info

  • Process info

  • Stores as memory or send instruction to trigger response

• Memory

  • Capacity to store and retrieve info

• Sources of info input

  • Sensory receptors

  • Envt

Spinal cord - Unconscious vs Conscious

CNS - Brain + spinal cord

Spinal cord

• integrating centre for info processing

• Does so unconsciously

unconscious

• when awake/asleep

• Involuntary

• Coor - brain and spinal cord

• Ex. Contraction of muscle, release of hormones

Conscious 

• Awake

• Voluntary

• Brain - cerebral hemispheres

• Ex. Thought, swallowing food

Structure of brain

Cerebral hemisphere

• Cerebrum

  • Control muscle func, speech, thought, emotions, reading, writing, learning

  • Structures

    • Right cerebral hemisphere

      • Muscle on left side of body

    • Left CH 

      • Muscle on RHS of body

  • Pri motor cortex

    • Control voluntary mvt to skeletal muscle (via motor neuron) → cause contract → bones move

• Cerebellum 

  • Coor skeletal muscle contraction 

  • Maintain balance

  • Motor memory

    • Ex. Riding a bike

• Grey matter

  • Cell bodies of motor + relay neuron w many synapses

    • Info integration occurs

• White matter

  • Axon fibres w myelin

    • Allow quick transmission of signal to brain, spinal cord, etc. 

Nervous system - sensory neuron (PNS)

• sensory neurons

  • Signal wn body tissue - detected by receptor → transmitted to CNS via sensory neuron

  • Ex. Photoreceptor, Chemoreceptors

Nervous system - Motor neuron (PNS)

• Transmit nerve impulse from CNS → transmitted to effector via motor neurons → result in mvt

Nerve

• Bundle of nerve fibre - Sensory, motor, myelinated, unmyelinated neuron

• enclosed within myelin sheated

• Facfilitate comm w specific region of body

Nerve fibre

• Afferent neuron - send signal to CNS via sensory neuron

• Efferent neuron - send signal away from CNA via motor neuron

Hypothalamus vs Pituitary gland

Hypothalamus → homeosttic control → regulate hormonal secretion via pituitary gland

• produce releasing factors → trigger release of hormones synthesised in pituitary gland 

• Produce hormones → directy released from pituitary gland

Pituitary gland → adjacent to hypothalamus

• Anterior and posterior lobe

• Control secretion of hormones from endocrine glands

Reflex arc

Involuntary response - allow allow fast action by activating spinal motor neuron instead of sending signal to brain

1. Pain stimulus deteced by receptor

2. Nerve impulse initiated in sensory neuron

3. Sensory neuron carry signal from sensory receptor to spinal cord

4. Synapse with relay neuron in grey matter

5. Relay neuron w motor neuron - leave spinal cord

6. Motor neuron - synapse with effector

7. Cause contraction → remove limb from pain stimulus

Circadian rhythm

Body normal physiolocal response to 24h day-night cycle

• driven by int circadian clock 

Melatonin

• hormone - produced by pineal gland wn brain

• responsible for synchronising circadian rhythm 

  • Regulate body sleep schedule

• Synced by light and dark

  • High secretion in dark → cause drowsiness + promotes sleep

  • Low secretion in light → promote waking up

• Effect:

  • Reduce bp, urine production

  • Drop core body temp

Epinephrine and effect on body

Amygdala → send stress signal to hypothalamus → initiate fight/fight response

Hypothalamus → stimulate release of epinephrine from adrenal gland above kidneys

Effect:

• Heart rate - elevated, strength of cardiac contractions increase 

  • Greater blood flow from heart

• More blood sent to skeletal muscle - o2 + glucose needed for a/anr respiration 

  Bronchioles widen → improve uptake of GE

• Liver → convert glycogen to glucose for transport to muscles

Cardiac output

Cardiac output

• auto controlled by medulla oblongata 

• varies accor to physiological requirements

Baroreceptor

• Location: Aortic walls + carotid arteries 

• Monitor bp → send neural signal to medulla oblongata accor to changes in bp

Chemoreceptor:

• Location: Aortic walls carotid arteries

• monitor blood pH + conc of o2 and co2 → stimulated when changes are made to pH → send neural signal to medulla oblongata 

Process of cardiac output

Based on signal sent to medulla oblongata from baro/chemoreceptor

• cardiovascular centre in MO 

  • process input → cause change in heart rate 

  • bring pH, conc of o2 and co2 back to target levels 

• Signal sent to SA and AV node → increase/decreate rate of heart beat

• I/D vol of blood entering lungs → I/D GE → I/D conc of o2+co2 in blood

Feedback control of ventilation rate

Ventilation → change in repsonse to physical activity, body e demnads increase

• ATP production → co2 produced as waste prodcut

• co2 → lower blood pH (via carbonic acid) → change in ph (deteced by chemoreceptor in medulla oblongata)

• Exercise intensity increase, co2 level increase, need for GE increase, increase in ventilation

Medulla oblongata

• signal to lungs + surrounding system to increase ventilation via:

  • Increase ventilation rate (more breaths) + volume (deeper breaths) 

ENS and CNS role in digestive system

Enteric nervous system

• neural pathways → coor digestion 

• Both autonomic and somatic motor pathways (involuntary + voluntary)

Swallow food + egestion of faeces 

• voluntary action - controlled by CNS 

Peristalsis 

• involuntary action - controlled by ENS

• Mechanism - enable food mvt along alimentary canal

  • ENS coor circular + longitudinal muscles → create wave-like contractions → push food forward

Phytohormones

Signalling chem - produced by plants

• regulate growth + dev processes 

• Examples:

  • Auxin - growth

  • Ethylene - ripening

  • Cytokinin - flowering

  • Gibberellins - trigger germination

  • Abscisic acid - leaf shedding + stomatal closure

Promotion of cell growth by Auxin

Plant hormone - increase flexibility of cell wall

• promote growth via cell elongation 

• Produced in apical meristem

Process:

• Activates protein pump in plasma membrane

  • Secrete H+ ions into apoplast

• pH of apoplast drops → Cell wall is being acidified

  • Activate expansins - enzyme

  • Break cross link btwn cellulose fibre

• Cell wall becomes more flexible + stretchable

  • Trigger K+ channel to open

    • Influx of K+ enter cytoplasm

  • Lower WP inside cell

    • h20 enter via osmosis (through aquaporin)

• Increase pa wn cell

  • Cause cyto to expand 

  • Wall stretches

• Lead to cell growth

Auxin Efflux Carrier (AEC)

Auxin 

• Freely diffuse INTO plant cell

• Cannot EXIT without specialised protein

Role of AEC:

• When inside the cell auxin becomes ionised in cyto → Prevents it from diffusing out

• To move auxin out of cell → rely on AEC

  • Specialised membrane proteins → AT charged auxin m across plasma membrane into cell wall

Process: 

• Auxin freely enter plant cell via diffusion

  • Undergo change in ionisation state → prevent passive efflux

• Auxin efflux carrier 

  • Transport auxin out of cell

  • Regulate auxin distribution

• Plants 

  • Able to position AEC on one side of cell 

    • Create conc gradient of auxin wn cell

• Auxin - actively transported from cell to cell through plant tissue

  • become conc in particular region of plant

Phototropism

Growth mvt of plant - respond to unidirectional light source

Process:

• Phototropins (light receptor) 

  • More light on one side

  • Phototropin on lit side activated, trigger redistribution of auxin to dark side of plant

    • Via coor positioning of auxin efflux carrier

• Auxin

  • promote cell growth + elongation of shaded cell

  • Cause shaded side of plant - become longer than lighter side

• Shoot tip bends towards light source (+ve phototropism)

Light → AEC moves to shaded side → Auxin builds up on shaded side →

H⁺ pumps activated → Cell wall acidifies → Expansins loosen wall →

Water enters → Cell elongates → Shoot bends toward light

Apical growth

Growth at tip of plant shoot + roots

Controlled by following hormones:

• Hormones need to be transported to region of plant they are NOT produced in

• Auxin

  • responsible for cell elongation

  • Produced in shoot tip of plant

  • Transported from plant → root (downward) via phloem

• Cytokin

  • Responsible for cell division

  • Produced in root tip of plant

  • Transported from roots → plant (upwards) via xylem

Interactions btwn phytohormones

• ensure root + shoot growth → regulated

• Auxin 

  • Promote root growth, inhibit shoot growth

• Cytokines 

  • Promote shoot growth, inhibit root growth 

• Differing conc 

  • Allow plant to adapt growth to diff envt + nutrient availability 

Ethylene

Phytohormone 

• maturation + ripening of certain types of fruits

• Sync ripening of fruit on plant

• Gas (produced as fruit begins rippening) - released from one plant → influence growth and maturation of another plant (allelopathy) 

  • Produce more ethylene in turn

• Ensure ripening process - rapid, not prolonged