Nervous SystemNervous SystemNervous SystemNervous SystemNervous System

heath care

1. CHAPTER 16
NERVOUS SYSTEM
PART 4
CYBELE DELGADO, M.D.
Source: Seeley's Essentials of Anatomy & Physiology (13th Ed.)

2. •Division of the nervous system that controls involuntary
functions.
•Regulates processes like heart rate, digestion, respiration, and
blood pressure.
•Works automatically to maintain homeostasis.
AUTONOMIC NERVOUS SYSTEM
Learning Outcome: Explain the basic function of the autonomic nervous system (ANS).

3. •Control of internal organs: Heart, lungs, digestive system, etc.
•Regulation of blood pressure, body temperature, and
respiratory rate.
•Helps respond to stress and emergencies (fight-or-flight
responses).
•Homeostasis: Ensures balance in bodily functions.
KEY FUNCTIONS
Learning Outcome: Explain the basic function of the autonomic nervous system (ANS).

4. Sympathetic Nervous System
•Known as the "fight or flight" system.
•Prepares the body for stressful situations.
•Increases heart rate, dilates airways, and inhibits digestion.
Parasympathetic Nervous System
•Known as the "rest and digest" system.
•Promotes relaxation and energy conservation.
•Slows heart rate, constricts airways, and stimulates digestion.
DIVISIONS
Learning Outcome: List the divisions of the autonomic nervous system.

5. Function
•Prepares the body for stress or emergency situations.
Neurotransmitter
•Primarily norepinephrine (noradrenaline).
Effects
•Increased heart rate and blood pressure.
•Dilation of pupils.
•Bronchodilation (dilation of airways).
•Inhibition of digestion.
SYMPATHETIC NERVOUS SYSTEM
Learning Outcome: List the divisions of the autonomic nervous system.

6. Function
•Restores and maintains energy.
Neurotransmitter
•Primarily acetylcholine.
Effects
•Decreased heart rate.
•Constricts pupils.
•Stimulates digestion and restoration of energy.
•Bronchoconstriction (narrowing of airways).
PARASYMPATHETIC NERVOUS SYSTEM
Learning Outcome: List the divisions of the autonomic nervous system.

7. Feature Sympathetic Parasympathetic
Primary Function Fight or flightRest and digest
NeurotransmitterNorepinephrine Acetylcholine
Heart Rate Increases Decreases
Respiratory Rate Increases Decreases
Digestive Activity Inhibits Stimulates
Pupil Size Dilates Constricts
COMPARISON
Learning Outcome: List the divisions of the autonomic nervous system.

8. Sympathetic
•Originates in the thoracolumbar region of the spinal cord (T1-
L2).
Parasympathetic
•Originates in the craniosacral regions (brainstem and sacral
spinal cord).
ANATOMY OF THE ANS
Learning Outcome: List the divisions of the autonomic nervous system.

9. Sympathetic System
•Releases norepinephrine from postganglionic neurons.
Parasympathetic System
•Releases acetylcholine from both pre- and postganglionic
neurons.
NEUROTRANSMITTERS
Learning Outcome: List the divisions of the autonomic nervous system.

10. Reflexes controlled by the ANS that help maintain homeostasis.
•Baroreceptor reflex (regulates blood pressure).
•Pupillary light reflex (controls pupil size).
•Salivary reflex (controls salivation).
AUTONOMIC REFLEXES
Learning Outcome: List the divisions of the autonomic nervous system.

11. •The hypothalamus plays a key role in regulating autonomic
functions.
•Brainstem (medulla) and spinal cord are also involved in
coordinating reflexes.
•Higher brain centers influence the autonomic system in
response to emotions or stress.
REGULATION OF THE ANS
Learning Outcome: List the divisions of the autonomic nervous system.

12. Orthostatic Hypotension
•A condition where blood pressure drops upon standing, often
due to ANS dysfunction.
•Common in older adults or patients on certain medications.
Parkinson’s Disease
•A neurodegenerative disorder that affects the ANS, leading to
symptoms like poor temperature regulation and constipation.
CLINICAL RELEVANCE
Learning Outcome: List the divisions of the autonomic nervous system.

13. THANK YOU!