biology C3.1

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define system integration

coordination of different biological systems so they work together to perform the functions of life

why is system integration needed to perform the functions of life?

it ensures communication, transport of nutrients, gases, and wastes, coordinated responses to internal/external changes

define tissue

group of similar cells that perform a specific function

define organ

structure amde fo two or more tissues working together

define organ system

group of organs that coordinate to perfomr major body function

how does integration occur between and among tissues, organs, and organ systems?

through signalling, transport, and defmechanial and chemical interactions

define emergent property

property that arises when samller components interact, producting functions not present in the individual parts

examples of emergent properties at each biolgoicallevel

cells —> tissues: contractility of muscle tissue

tissues —> organs: pumping ability of the heart

organs —> organ systems: blood circulation

systems —> organism: homeostasis

primary mechanisms of integration

nervous system

endocrine (hormonal) system

nervous signal type

electrical + neurotransmitters

hormonal signal type

chemical hormones

nevous transmission

neurons

hormonal transmission

bloodstream

nervous speed

very fast

hormonal speed

slower

nervous duration

short-lived

hormonal duration

long-lasting

nervous response

local, targeted

hormonal response

widespread

role of blood in material/energy transport

carries nutrients, waste, gases, hormones

distributes heat

links all organs for coordinated functioning

function of the brain

central processing unit for sensory information, coordination, learning, memory and voluntary control

sources of input to the brain

sensory receptors

body’s internal environment

signals from the spinal cord

organs of the CNS

brain and spinal cord

conscious processing

voluntary, controlled by cerebral cortex; slow

unconscious processing

automatic reflexes; no awareness needed

types of sensory receptors

photoreceptors

mechanoreceptors

chemoreceptors

thermoreceptors

nociceptors

function of sensory neurons

carry signals from receptros to CNS

location and function of motor output

cerebral hemisphere: conscious though and voluntary movement

primary motor cortex: initiates voluntary muscle contraction

skeletal muscles: effectors that contract to produce movement

function of motor neurons

carry signals from CNS to muscles

define nerve

bundle of axons from many neurons

strctures visible in a nerve cross-section

axons

connective tissue layers

blood vessels

myelin sheath

define reflex

automatic, rapid response to a stimulus

define reflex arc

neural pathway that produces a reflex

steps in a pain reflex arc

1. Receptor: Detects stimulus (pain)

2. Sensory neuron: Sends signal to spinal cord

3. Interneuron: Processes information

4. Motor neuron: Carries response signal

5. Effector: Skeletal muscle contracts

location of cerebellum

below cerebum, back of brain

function of the cerebellum

coordinate muscle movement

maintain balance

fine-tune motor activity

define circadian rhythm

24-hour cycle regulating physiological

role of SCN

master clock in hypothalamus

synchronises body rhythms

how SCN responds to light

recieves light signals from retina

adjusts rhythm and melatonin release

define melatonin

secreted by pineal gland

released in darkness to induce sleepiness

mechanism of action for melatonin

Binds to receptors in brain → reduces alertness → promotes sleep.

effects of melatonin

sleep onset

lower body temperature

reduced alertness

how is adrenaline secreted

by adrenal glands during stressful activity

adrenaline mechanism of action

binds receptors on targer organs

activates second-messenger pathways

effects on the body

skeletal muscles: increased blood flow —> more oxygen

liver: glycogen —> glucsoe

bronchi: dilate

ventiliation rate: increases

heart rate: increase

blood vessels: dilate in muscles; constrict in others

role of hypothalamus

link between nervous and enfocrine systems

processes monitored by hypothalamus

temperature

water balance

hunger

stress

hormone levels

factors increasing heart rate

low blood pressure

high CO2

exercise

stress

factors decreasing heart rate

high blood pressure

low CO2

parasympathetic stimulation

epinephrine source and effect

adrenal glands —> increases heart rate

effect of exercise on CO2

CO2 production increases

ventilation feedback loop

1. CO₂ rises → pH falls

2. Chemoreceptors detect change

3. Brainstem increases ventilation

4. Diaphragm & intercostal muscles contract more

5. CO₂ expelled → pH restored

hyperventilation in exercise

occurs to remove CO2 quickly and maintain pH

how does CNS regulate gut movement

adjusts speed/intensit

examples of voluntary control

swallowing

examples of involuntary control

secretion

myogenic heart rate

heart contracts on its own due to pacemaker cells in the SA node

intristic rate can be modifed by neural signals and endocrine signals

key structures involved in regulating heart rate

medulla oblongata: cardiac control center

sympathetic nerve: increase heart rate

vagus nerve: decreases heart rate

baroreceptors: detects blood ressure

chemoreceptors: detect CO2/pH