Nervous system for nurses

Homeostasis

A condition of equilibrum in the body's internal environment produced by the ceaseless interplay of all the body's regulatory processes.

- Maintains the internal environment within physiological limits.

- Examples; Blood glucose level
-Thermoregulation
-Osmoregulation

Control of Homeostasis

Homeostasis is regulated by the nervous system and endocrine system, acting together or independently.

- The nervous system; detects changes and sends nerve impulses to counteract the disruption

-The endocrine system; regulates homeostasis by secreting hormones

-Hormones work slowly
-Nerve impulses cause rapid changes

Homeostasis

-Maintains the internal environment within physiological limits.

Homeostasis and Aging

Aging is characterised by a progressive decline in the body's responses to restore homeostasis.

-These changes are apparent in all the body systems.
-crinkled skin, loss of bone mass, slower responses to changes in blood pressure.

Homeostasis and the Nervous system

-Nerve impulses pass along neurons to organs
-Rapid (milliseconds) precise response

Homeostasis and the endocrine system

Endocrine glands send hormones via blood to organs

Homeostasis and the endocrine system

Hormonal response

Sensory functions (PNS)

-Receptors sense changes in inter/external environment
-Sensory (afferent) neurons conduct sensory impulses

Sensory neurons

Afferent

Intergrative function (CNS)

-Analyze and store sensory information
-Make decisions regarding appropriate responses
-Interneurons serve this function

Motor function (PNS)

- Respond to stimuli by initiating action
-Motor (efferent) neurons conduct motor impulses to effectors (muscles and glands)

Motor neurons

Efferent

Central Nervous system contains

Brain and spinal cord

Peripheral nervous system

- Cranial nerves (12 pairs)
-Spinal nerves (31 pairs)

Crainal nerves

-12 pairs
-attached to the base of the brain

Spinal nerves

- 31 pairs
- Attached to the spinal cord

Main functional divisions of the PNS

-Somatic
-Automatic
-Enteric

Somatic N.S

Voluntary, conscious

Autonomic n.s

Involuntary, subconscious

Enteric n.s

Involuntary, subconscious

Parasympathetic

Rest and digest

Sympathetic

Fight or Flight

Autonomic Nervous system

Parasympathetic n.s
Sympathetic n.s

Sympathetic n.s

Prepares the body for emergencies or energy expenditure

Somatic n.s - SNS

Structure; nerve fibres form part of both cranial and spinal nerves

Somatic n.s - SNS

Function; carries sensory input about body sensations and special senses to the CNS

- Carries motor output away form the CNS- allows conscious control of skeletal muscles (voluntary)

Autonomic n.s - ANS

Structure; Nerve fibres part of both cranial and spinal nerves

Autonomic n.s - ANS

Function; Subconscious control of organs and glands
-Carries sensory input from visceral (internal organs) receptors to the CNS
-Carries motor output to smooth muscle, heart muscle and/or glands (involuntary)

Enteric Nerve Plexus

Gastrointestinal (GI) tract has its own sensory/ coordinating/ motor neurons

Enteric Nerve Plexus, functions

Functions; To control GI muscle contraction and gland secretion
-involuntary sensory & motor neurons
-many neurons function independently of ANS & CNS

Nervous system function- general model.

1, Sensory receptor
2, Sensory Neuron
3, Integrating center
4, Motor neuron
5, Effector