THE-ENDOCRINE-SYSTEM-NERVOUS-SYSTEM-AND-REPRODUCTIVE-SYSTEM

THE ENDOCRINE SYSTEM

• Controls body activities via hormones produced by glands affecting target cells.

• Two types of glands:

  • Endocrine Glands: Release hormones into the bloodstream.

  • Exocrine Glands: Release secretions through ducts.

• Endocrinologist: Physician specializing in endocrine gland diseases.

PITUITARY GLAND

• Produces hormones and regulates various glands.

• Referred to as "the Master Gland" and controlled by the hypothalamus.

• Composed of:

  • Anterior Lobe: Secretes hormones such as:

    • Prolactin

    • Gonadotropic Hormones (LH, FSH)

    • Thyroid-Stimulating Hormone (TSH)

    • Adrenocorticotropic Hormone (ACTH)

    • Growth Hormone

  • Posterior Lobe: Extension of the hypothalamus, secretes:

    • Antidiuretic Hormone (ADH): Decreases urine excretion, conserves water.

    • Oxytocin: Promotes milk letdown in lactating mothers.

THYROID GLAND

• Located at the neck's base, flanking the trachea.

• Secretes:

  • Thyroxine (T4) and Triiodothyronine (T3) (need iodine for production).

  • Calcitonin: Lowers blood calcium levels.

HYPOTHYROIDISM

• Characterized by an underactive thyroid gland.

• Effects include:

  • Decreased metabolic rate

  • Slowed heartbeat, lower blood pressure, and body temperature

• Possible complications:

  • Cretinism: Mental and physical retardation.

  • Myxedema Coma: Severe, life-threatening condition.

  • Goiter: Abnormal enlargement of the thyroid gland due to iodine deficiency.

HYPERTHYROIDISM

• Condition of an overactive thyroid gland.

• Grave's Disease: The most common cause of hyperthyroidism.

ADRENAL GLANDS

• Located above the kidneys.

• Composed of:

  • Adrenal Medulla: Secretes epinephrine and norepinephrine (emergency hormones).

  • Adrenal Cortex: Secretes:

    • Cortisol: Stress hormone.

    • Aldosterone: Regulates water and salt balance.

THE NERVOUS SYSTEM

• Composed of:

  • Central Nervous System (CNS)

  • Peripheral Nervous System (PNS)

CENTRAL NERVOUS SYSTEM (CNS)

• Integrates receptor and effector functions for responses.

• Brain: Center of knowledge, emotions, learning, and awareness.

  • Weighs ~1.4 kg and consists of over 100 billion neurons.

BRAIN STRUCTURE

• Major parts:

  • Cerebrum: Largest part, responsible for higher brain functions.

    • Cerebral Cortex: Outer layer integrating information.

  • Cerebellum: Coordinates movement and motor function.

  • Brainstem: Includes the hypothalamus, thalamus, medulla oblongata, and pons.

    • Hypothalamus: Regulates body temperature, emotions, thirst, hunger.

    • Thalamus: Relays sensory/motor impulses, regulates sleep and alertness.

    • Medulla Oblongata: Regulates breathing and heartbeat.

    • Pons: Connects cerebrum with medulla oblongata.

SPINAL CORD

• Extends from the base of the brain to below the last rib, protected by the vertebral column.

• Communicates with the body via 31 pairs of spinal nerves.

PERIPHERAL NERVOUS SYSTEM

• Composed of nerves connecting the nervous system to the body's parts.

NERVES

• Composed of tissues that link the nervous system to different body parts.

• Epineurium: Outermost sheath.

• Perineurium: Covers bundles of nerve fibers.

• Endoneurium: Innermost sheath surrounding individual nerve fibers.

HUMAN REPRODUCTIVE SYSTEM

• Puberty: Physical changes marking sexual maturity.

SECONDARY SEX CHARACTERISTICS

• Includes development of body hair, muscle growth, broadening shoulders, voice box enlargement, hip broadening, and breast development.

FUNCTIONS OF THE REPRODUCTIVE SYSTEM

• Male Reproductive System: Produces male sex cells, deposits sperm in the vagina.

• Female Reproductive System: Produces female sex cells, receives sperm, nurtures developing offspring.