Nervous system

- Divisions of the nervous system- The brain

Stimuli

RECEPTORS

SENSORY NEURON

MOTOR NEURON

EFFECTOR

In which form is the message carried by the sensory and the motor pathways? By nerve impulses

Muscles Glands

Contraction SecretionResponse

What 2 types of effectors are there?

What is the result of their stimulation?

The nervous system analyses sensory information from the body and the external environment

The information is analysed and appropriate voluntary and involuntary motor responses are made which lead to muscular contractions or glandular secretions

Some of the information is stored for future use.

What is the function of sensory neurons?Carry impulses from receptors to the CNS.

What is the function of motor neurons?Carry impulses from the CNS to effectors.

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NERVOUS SYSTEM

CENTRALNERVOUS SYSTEM

PERIPHERALNERVOUS SYSTEM

BRAINSPINALCORD

Structural division of the nervous system

• In which 2 parts can the peripheral nervous system be divided in?

• Somatic Nervous System (SNS)• Autonomic Nervous System (ANS)

• What is the function of the Somatic NS?• Sensory and motor neurones of the somatic nervous

system (SNS) control the mostly voluntary movement of skeletal muscles.

• Example of functions controlled by the Somatic NS?• Walking and speaking

• What is the function of the Autonomic NS?• To regulate the internal environment by the

involuntary control of the heart, alimentary canal, blood vessels and bronchioles.

• What is the name given to the maintenance of the body’s internal environment within certain tolerable limits despite changes in the body’s external environment?

• Homeostasis

• In which 2 parts can the autonomic nervous system be divided in?

• Sympathetic Nervous System (SNS)• Parasympathetic Nervous System (PNS)• These two systems affect many of the

__________structures but have __________effect on them.

• They are said to be______________.

same opposite

antagonistic

• In broad terms, homeostatic control is through sensory neurons and motor neurons conducting involuntary impulses to what?

• Smooth muscle, cardiac muscle and glands.

• Sympathetic NS:• Effect on cardiac muscle?• Increased rate and force of contractions result in

increased cardiac output• Effect on smooth muscle of the walls of the

digestive system?• Decreased rate of peristalsis• Effect on smooth muscles in wall of bronchioles?• Tube bore dilates resulting in an increased volume

of air to enter lungs• Effect on adrenal gland?• Increased rate of secretion of adrenaline

• Parasympathetic NS:• Effect on cardiac muscle?• Decreased rate and force of contractions result in

decrease cardiac output• Effect on smooth muscle of the walls of the

digestive system?• increased rate of peristalsis• Effect on smooth muscles in wall of bronchioles?• Tube bore constrict resulting in a decreased

volume of air to enter lungs• Effect on adrenal gland?• No effect- no