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The nervous and endocrine system, Human nervous system - Coggle Diagram
The nervous and endocrine system
The nervous system
Network of cells
Primary internal communication system
Based on electrical and chemical signals
Two main functions
To collect, process and respond to info in environment
To co-ordinate working of different organs and cells in body
Central Nervous System (CNS)
Made up of brain and spinal chord
Brain
Centre of all conscious awareness
Outer layer, Cerebral Cortex, only 3mm thick and covers brain like an orange peel. Only found in mammals
Highly developed in humans and distinguishes our higher mental functions from that of other animals.
Divided into two hemispheres
Spinal Chord
Extension of brain
Passes messages to and from brain and connects nerves to PNS
Responsible for reflex actions
Peripheral Nervous System (PNS)
Transmits messages via millions of neurons to and from CNS
Two systems
Autonomic Nervous System (ANS)
Governs vital functions in body eg. breathing, heart rate, digestion, sexual arousal and stress responses
Somatic Nervous System (SNS)
Governs muscle movement and receives info from sensory receptors
Endocrine System
Glands and Hormones
Works alongside nervous system to control vital functions
Acts more slowly than nervous system but has powerful widespread effects
Various glands in body such as thyroid gland, produce hormones
Secreted in blood stream and affect any cell in body that has a receptor for that hormone
Most hormones affect cells in more than one body organ
E.g. thyroid gland produces thyroxine. This hormone affects cells in heart, and cells throughout the body increasing metabolic rates affecting growth rates.
Main gland is pituitary gland
Located in the brain
Controls release of hormones from all other endocrine glands in body - Master gland
Endocrine and ANS working together: Fight or Flight
Often endocrine system and ANS work in parallel for example in a stressful situation
When stressor is perceived the hypothalamus activates the pituitary gland and triggers activity in sympathetic branch of ANS. ANS changes from normal resting state (parasympathetic state) to physiologically aroused sympathetic state.
Adrenaline
Stress hormone that is released from adrenal medulla (near kidneys) into bloodstream. Triggers physiological changes in body which creates physiological arousal needed for fight or flight response.
Immediate and automatic
Happens in an instant as soon as threat is detected.
Parasympathetic action
Once threat has passed, Parasympathetic system returns body to resting state - rest and digest response
Human nervous system
Peripheral nervous system
Autonomic nervous system
Sympathetic nervous system
Parasympathetic nervous system
Somatic nervous system
Central nervous system
Brain
Spinal chord