olfactory

Overview of the Olfactory and Pharyngeal Systems

  • Two models observed: lateral view of the nasal cavity and nociceptive view.
  • Key structures of the olfactory system highlighted.

Nasal Concha

  • Nasal conchae are the folds observed in the nasal cavity.
  • There are three nasal conchae:
    • Superior nasal concha
    • Middle nasal concha
    • Inferior nasal concha
  • Function:
    • The term "concha" refers to a shell shape.
    • The conchae help to warm and humidify the cold air entering at room temperature.
    • Facilitates air direction through the nasal cavity.

Nasal Meatus

  • The meatus is the canal structure created by the conchae's folds.
    • Superior nasal meatus
    • Middle nasal meatus
    • Inferior nasal meatus

Pharynx Structure

  • Divided into three parts:
    • Nasal pharynx: posterior to the nostrils, involved in respiratory function.
    • Oral pharynx: middle portion that connects the mouth and throat.
    • Laryngopharynx: lower part that leads to the larynx and esophagus.
  • During breathing, air travels through these cavities.
  • Epiglottis: a flap to prevent food from entering the trachea during swallowing.

Uvula

  • The uvula (U-shaped structure) prevents food from entering the nasal cavity when swallowing.
  • Functions as an additional gate along with the epiglottis.

Olfactory Function

  • The sensation of smell involves the olfactory bulb and tract, connected by the cribriform plate, which has small holes known as olfactory foramina.
    • Olfactory nerve (Cranial Nerve I): pathway for smell sensation.
  • Air passes through the olfactory foramina, where receptors are located.
  • The limbic system is involved in the emotional response to smells, triggering memories (e.g., baby powder scent).

Transition to Endocrine System

  • Introduction of the endocrine system and its functions.
  • Hormones: chemical messengers produced by the endocrine system for regulating bodily functions,
    • Hormones act slowly compared to the nervous system due to their release into the bloodstream.
    • Example: estrogen influences the menstrual cycle (28 days).

Comparison Between Nervous and Endocrine Systems

  • Nervous System: fast-acting with neurotransmitters (e.g., acetylcholine).
  • Endocrine System: slow, releasing hormones into the bloodstream.

Pituitary Gland

  • Joins endocrine and nervous systems, located in the brain.
  • Consists of:
    • Anterior Pituitary (produces FSH, LH, ACTH, TSH, GH, PRL)
    • Posterior Pituitary (stores and secretes ADH and oxytocin).
  • Key terms:
    • FSH (Follicle Stimulating Hormone): stimulates follicle growth.
    • ACTH (Adrenocorticotropic Hormone): stimulates adrenal glands.
    • Thyroid Stimulating Hormone (TSH): stimulates thyroid gland.
    • Endorphins: hormones that relieve pain and induce positive feelings.

Lab Preparation

  • Students will prepare for the upcoming lab exam covering the olfactory and endocrine systems, focusing on hormonal functions and anatomical locations.

Summary of Definitions and Important Points

  • Olfaction: sense of smell, involving nasal structures and the limbic system.
  • Hormones: key regulators in the body released by glands like the pancreas and thyroid.
  • Understanding the structure and function of the pituitary gland will be crucial for the next lab session.