Human Body Function (HBF) 102 Overview

Course Information

• Academic Year: 2024-2025
• Year: 1
• Semester: 1
• Module: Human Body Function (HBF) 102

Lecture Objectives

• List the controlling systems of the human body
• Demonstrate the components of the nervous system
• Explain the importance of the autonomic nervous system
• Compare somatic and autonomic reflex arcs
• Distinguish the general divisions of the autonomic nervous system

Control of Our Body: Endocrine Glands

• Pituitary gland
• Thyroid gland
• Pancreas
• Kidney
• Ovaries (female)
• Testes (male)
• Hypothalamus
• Pineal gland
• Parathyroid glands (behind thyroid)
• Thymus gland
• Stomach
• Adrenal glands
• Adipose tissue
• Small intestine

Control of Our Body: Nervous System

• Brain
• Spinal cord
• Nerves

Components of the Nervous System

• Central nervous system (CNS)
• Peripheral nerves

Nervous System: Divisions

• Central Nervous System
  • Brain
    • Cerebrum
    • Cerebellum
    • Brain stem
      • Midbrain
      • Pons
      • Medulla
  • Spinal cord
• Peripheral Nervous System
  • Cranial nerves
  • Spinal nerves
• Autonomic Nervous System
  • Heart muscle
  • Smooth muscle
  • Glands
• Somatic Nervous System
  • Voluntary skeletal muscles
• Parasympathetic Division
  • "Rest and digest"
• Sympathetic Division
  • "Active and alert"

Peripheral Nervous System Classification

• Central nervous system (CNS)
  • Brain
  • Spinal cord
• Peripheral nervous system
  • Peripheral nerve
  • Aferrent (sensory)
  • Efferent (motor)
    • Autonomic (involuntary)
      • Parasympathetic
      • Sympathetic
        • Adrenal Medulla
    • Somatic (voluntary)

The Reflex Arc

• The basic functional unit of the nervous system
• The pathway for reflex action.

Reflex Arc: Components

• Receptor
• Afferent nerve
• Center
• Efferent nerve
• Effector organ

Differences Between Somatic and Autonomic Reflex Arcs

• Afferent somatic nerves relay in the dorsal or ventral horns of the spinal cord. Afferent autonomic nerves relay at lateral horn cells.
• Efferent somatic nerves arise from the ventral horn cells of the spinal cord, while efferent autonomic nerves arise from the lateral horn cells.
• Efferent somatic fibers go directly to skeletal muscles, while efferent autonomic fibers relay in autonomic ganglia before supplying the effector organ.
• Efferent somatic nerves supply skeletal muscles only. Efferent autonomic nerves supply various tissues (heart, smooth muscles, glands, adipose tissue, gastrointestinal tract).
• Somatic nerve impulse is excitatory only, autonomic impulse is excitatory or inhibitory.
• Nerve fibers in the somatic system are fast-conducting, thick (9-13 µm), and myelinated. Nerve fibers in the autonomic system are slow-conducting, lightly myelinated or unmyelinated, and thin (about 1 µm).

The Integrative Nervous System

• Concerned with sophisticated brain functions
• Includes memory, thinking, learning, language, speech, emotions, and general behavior

Autonomic Nervous System Importance

• Responsible for involuntary vital functions
• E.g., cardiovascular, respiratory, and gastrointestinal systems
• Dysfunction of the ANS can cause diseases and death
• Many medicines affect the ANS to treat diseases

Divisions of the Autonomic Nervous System

• Sympathetic
  • System is activated all at once.
• Parasympathetic
  • System is not activated all at once and generally does the opposite of sympathetic functions.
• Enteric
  • Localized to the alimentary tract
  • Two plexuses (submucosal and myenteric)

Summary of Human Nervous System and Body Control

• The human body is controlled by the endocrine and nervous systems interconnected for integrated functions.
• The nervous system includes the central nervous system (brain and spinal cord) and the peripheral nervous system (cranial and spinal nerves).
• The nervous system is divided into somatic (voluntary) and autonomic (involuntary) systems.
• The autonomic system is further divided into sympathetic, parasympathetic, and enteric nervous systems.

This quiz covers the essential components and controlling systems of the human body, focusing on the nervous and endocrine systems. It will test your understanding of the various glands and the structure of the nervous system. Prepare to explore the integral roles these systems play in maintaining homeostasis.