C.3.1 - Integration of body systems

Body systems for communication

• Nervous system (receptors send signals to muscles) - electrical signals

• Endocrine system (glands respond to chemical signalling and release hormones) - hormones signal chemically, transported in bloodstream

Negative feedback control

The body’s system of retaining homeostatic conditions (body temmperature, glucose levels, blood pressure, digestion, etc.)

Emergent properties

Properties that appear in a complete organism but aren’t present in its individual components

Autonomic nervous system (ANS)

Part of nervous system that communicates with the brain without conscious knowledge

Target tissue of a hormone

The body tissue where a certain hormone produces an effect

Exp. of the nervous and endocrine systems working together

Release of adrenaline hormone is triggered by information passed on by the nervous system. Sensory organs transmit information to the nervous system, indicating that adrenaline is needed as part of a fight-or-flight response. ANS then sends impulses to the adrenal glands to release adrenaline.

Nervous system characteristics

• Electrical impulses send messages

• Neurons are used to transmit and recieve impulses

• Parts control volontary actions, parts control involontary

• Responses are quick and short-lived

Endocrine system characteristics

• Hormones send messages

• Hormones travel through bloodstream

• Only involontary functions are controlled

• Responses are slow but long-lasting

Brain receptors (conscious level)

• Photoreceptors - retina, process visual info

• Chemoreceptors - tongue, process tastes

• Thermoreceptors - skin, process temeperature changes

• Mechanoreceptors - inner ear, process loud vibrations

Brain receptors (subconscious level)

• Osmoreceptors - carotid artery, hypothalamus, regulate blood water levels and solute levels

• Baroreceptors - carotid artery, aorta, sense blood pressure

• Proprioceptors - muscles and joints, provide balance and coordination

How does the brain communicate with the body?

• Spinal nerves (31 paired nerves emerging from spinal cord)

• Cranial nerves (12 paired nerves connected to the brainstem)

Three main parts of the brain

• Cerebrum

• Cerebellum

• Brainstem

Cerebrum

• Divided into right and left cerebral hemispheres

• Each hemisphere contains frontal, temporal, parietal, and occipital lobes

• Controls conscious activities

  • Frontal lobe coordinates memory & learning activities

Cerebellum

Coordinates volontary movements; controls balance + equilibrium

Brainstem

• Relays impulses between cerebrum, cerebellum, and spinal cord

• Controls subconscious functions neccessary for life (e.g. medulla regulates breathing and heart rate)

Spinal cord cell types

• White matter (axons + neurons, carries neural impulses to and from the brain)

• Grey matter (neurons + synapses)

Reflex arc

Pathway of an impulse

Hormone def

• Produced in the glands

• Secreted into the bloodstream

• Acts on a target cell

Regions of spinal cord

• Cranial nerves (facial movement)

• Cervical region (head neck & upper body)

• Thoracic region (torso, hands & fingers)

• Lumbar region (legs)

• Sacral region (bowel & bladder, sexual function)