Human Physiology Hormones and Senses Quiz

Sensory Systems

• Sensory vs. Perception: For perception to occur, the sensory signal must reach the cerebrum.
• Sensory Adaptation: The ability to no longer perceive sensations due to prolonged exposure.
• Sensory Receptors: Classified by distribution, location, and type.
  • Free Nerve Endings: Detect pain, temperature changes, itch, and tickle.
  • Encapsulated Nerve Endings: Detect touch, pressure, vibration.
  • Special Sensory Cells: Used for specialized sensory reception.
• Classification by Location:
  • Exteroceptors: Sensations from outside the body.
  • Interoceptors: Sensations from inside the body.
  • Proprioceptors: Sense body position and movement.
• Classification by Type:
  • Mechanoreceptors: Detect stretch (touch, pressure, vibration, stretch, and proprioception).
  • Osmoreceptors: Detect osmolarity.
  • Thermoreceptors: Detect temperature.
  • Chemoreceptors: Detect chemicals.
  • Photoreceptors: Detect light.
  • Nociceptors: Detect pain (fast/acute and slow/chronic).
• Referred Pain: Pain felt in a location other than the origin. Common sites often discussed in the relevant material.
• Tactile Receptors: Detect touch, pressure, vibration, itch, and tickle.
  • Free Nerve Endings: Touch, itch, tickle, temperature change, and pain.
  • Root Hair Plexuses: Detect movement on skin by hair movement.
  • Corpuscles:
    • Meissner's Corpuscle: Light touch and low frequency vibration.
    • Merkel Cells: Pressure.
    • Ruffini's Corpuscle: Light and deep pressure (baroreceptors).
    • Lamellated Corpuscles (Pacinian Corpuscle): Vibration.

Visual System

• Special Sensory Receptors: Rods and cones (photoreceptors) in the retina.
• Visible Light: Based on wavelength.
• Layers of the Eye: Anterior and posterior segments.
  • Fibrous Tunic: Sclera (protective outer layer of dense irregular connective tissue) and cornea (transparent front for light passage).
  • Vascular Tunic: Choroid (mostly containing blood vessels behind retina), ciliary body (contains muscle, processes, and zonular fibers) and iris (regulates pupil size).
  • Retina: Photoreceptor layer (rods and cones), bipolar cells, ganglion cells, and horizontal/amacrine cells. Contains the Optic Disc where the optic nerve exits and blood vessels enter the eye.
  • Chambers: Anterior chamber (aqueous humor) and vitreous chamber (vitreous humor).
• Visual Pathways: Light refraction through cornea, aqueous humor, pupil, lens (accommodates to focus light), vitreous chamber to retina. Signal sent through optic disc to optic nerve (CN II), optic chiasm, optic tracts, thalamus, optic radiations, and finally to the occipital lobe.
• Optic Nerve (CN II): Carries visual information to the brain.
• Occipital Lobe: Processes visual information.

Olfaction

• Special Sensory Receptors: Olfactory cells of olfactory membrane (chemoreceptors).
• Olfactory Pathways: Olfactory cells send signals to olfactory nerve (CN I), olfactory bulb, olfactory tracts, limbic system, and temporal/frontal lobes.

Gustation

• Special Sensory Receptors: Gustatory cells within taste buds (chemoreceptors).
• Gustatory Pathways: Signals to facial nerve (CN VII) – anterior 2/3 tongue; glossopharyngeal nerve (CN IX) – posterior 1/3 tongue; and vagus nerve (CN X) – epiglottis. Signals pass to medulla oblongata, thalamus, and parietal lobe.
• Taste Papillae: Vallate (12, 100–300 buds), fungiform (scattered, 5 buds), foliate (lateral trenches, degenerate), filiform (no buds, tactile).

Auditory System

• Special Sensory Receptors: Organ of Corti within cochlea (mechanoreceptors).
• Auditory Pathway: Sound travels from outer ear (auricle, external auditory canal, tympanic membrane) to middle ear (eustachian tube, ossicles, oval window, round window) to inner ear (bony labyrinth, cochlea, organ of Corti). Signal travels via cochlear portion of vestibulocochlear nerve (CN VIII) to temporal lobe.
• Equilibrium: Maculae of utricle and saccule detect linear acceleration/deceleration; cristae in semicircular canals detect rotation. Otoliths help with head rotation detection. Signal sent via vestibular portion of vestibulocochlear nerve (CN VIII) to brain.

Endocrine System

• General Functions: Metabolism, growth, sleep, mood, tissue function, reproduction, stress, and fluid dynamics.
• Primary Endocrine Structures: Structures solely for hormone production (pineal, pituitary, thyroid, parathyroid, adrenal).
• Secondary Endocrine Structures: Produce hormones as a secondary function (pancreas, thymus, skin, heart, stomach, liver, kidneys, hypothalamus, gonads, small intestine).
• Chemical Classification of Hormones/Mechanism of Action:
  • Lipid-Soluble: Bound to transport proteins, receptors inside cells (e.g., nucleus). (steroids, thyroid hormones, nitric oxide)
  • Water-Soluble: Circulate freely, receptors on outer cell membrane. (amines, peptides, proteins, glycoproteins, eicosanoids)
• Control of Hormone Secretion: Hormonal stimuli, neural stimuli, and humoral stimuli.
• Hypothalamus-Pituitary Connection: Hypothalamus connects to anterior pituitary via blood vessels (hypophyseal portal system) and to posterior pituitary via nerves.
• Hypothalamic Hormones Stimulating the Anterior Pituitary: Examples include GHRH, TRH, GnRH, PRH, CRH.
• Anterior Pituitary Hormones and their Targets/Effects: Growth Hormone (GH), Thyroid-Stimulating Hormone (TSH), Follicle-Stimulating Hormone (FSH), Luteinizing Hormone (LH), Prolactin (PRL), Adrenocorticotropic Hormone (ACTH), Melanocyte-stimulating hormone (MSH).
• Posterior Pituitary Hormones and their Targets/Effects: Oxytocin, Antidiuretic Hormone (ADH).
• Endocrine Structures and Hormones (examples): Thyroid (T3, T4, calcitonin), Parathyroid (PTH), Adrenal (aldosterone, cortisol, adrenal androgens, epinephrine, norepinephrine), Pancreatic Islets (glucagon, insulin), Ovaries and Testes (estrogens, progesterone, testosterone, relaxin, inhibin).
• Local Chemical Messengers and Hormonal Interactions: Autocrine, paracrine, eicosanoids, and hormonal response to stress (eustress, distress, fight-or-flight, resistance, exhaustion).
• Disruptions of Homeostasis: Pituitary gigantism, acromegaly, pituitary dwarfism, Graves' disease, goiters, Cushing's syndrome, Addison's disease, diabetes mellitus (Type 1 and Type 2).