LAB 2 PDF - Cranial Nerves, The Brain, Spinal Cord, Spaces, Thyroid & Parathyroid, Adrenal Gland

# **LAB 2** ## **Cranial Nerves** **Ventral view** - **(1) Olfactory bulbs:** Sensory nerve for smell and originates in mucosa of nose; terminates on anterior portion of cerebral hemisphere - **(2) Olfactory tract:** brings info to temporal lobe for interpretation - **(3) Optic:** Sensory nerve f...

# **LAB 2** ## **Cranial Nerves** **Ventral view** - **(1) Olfactory bulbs:** Sensory nerve for smell and originates in mucosa of nose; terminates on anterior portion of cerebral hemisphere - **(2) Olfactory tract:** brings info to temporal lobe for interpretation - **(3) Optic:** Sensory nerve for vision that originates in the retina and triggered when light hits photoreceptors in the eye - **(4) Optic chiasma:** two optic nerves converged forming an X on anterior portion of brain - **(5) Oculomotor:** motor nerve and originates from lateral portion of midbrain and travels to extrinsic eye muscles - **(6) Trigeminal:** a mixed cranial nerve (motor & Sensory) that originates from junction between midbrain and pons; sensory portion impacts facial sensation from oral/nasal cavities; motor portion impacts mastication (chewing) and swallowing - **(7) Midbrain:** inferior to diencephalon; eye movement, vision, hearing - **(8) Pons:** inferior to midbrain; connects medulla oblongata to cerebellum and higher brain centres - **(9) Medulla oblongata:** between pons and spinal cord; controls vital aspects of cardiovascular and respiratory function ## **The Brain** **Dorsal view** - **(1) Cerebellum:** posterior to cerebrum and divided from cerebrum by transverse fissure; movement - **(2) Cerebrum:** gyri (bumpiness) on the surface; sulci or fissures are clefts that define gyri - **(3) Longitudinal cerebral fissure:** divides two hemispheres - **(4) Corpus callosum:** band of white matter for communication between hemispheres - **(5) Frontal lobe:** anterior most; primary motor area and motor speech area - **(6) Parietal lobe:** posterior to F.L. i primary Somatosensory area, Somatosensory association area, primary gustatory area - **(7) Temporal lobe:** inferior to F.L. & P.L.; primary auditory, auditory association areas, primary olfactory - **(8) Occipital lobe:** most posterior lobe: primary visual and visual association areas - **Cerebral cortex:** comprised of grey matter ## **The Brain** **Midsagittal section** - **(11) Thalamus:** wall of diencephalon; controls info that reaches cerebral cortex - **(12) Hypothalamus:** sit inferior to thalamus; regulation of circadian rhythm, thirst, hunger, body temperature and pituitary gland - **(13) Pituitary:** sits just below hypothalamus - **(14) Pineal glands:** housed in diencephalon; secreting melatonin ## **Spinal Cord and Spinal Nerves** - **(1) Grey matter:** "H" shaped region with anterior horns and posterior horns ("arms"); inner region; processing of information - **(2) White matter:** outer region; divided into columns seperated by grey matter horns; high speed conductors of nerve impulses - **(3) Central canal:** centre of grey matter continuous with the cavities of the brain and filled with cerebrospinal fluid - **Spinal Nerves: 31 pairs** - **(4) Anterior (motor) nerve root:** axons of motor neurons which carry impulse responses to effector sites - **(5) Posterior (sensory) nerve root:** presence of slightly enlarged area called Spinal (dorsal root) ganglion; sensory neurons that relay information back to spinal cord - **(6) Spinal ganglion** - **(7) Anterior horns** - **(8) Posterior horns ** - **(9) Central canal** ## **Spaces / Meninges** - **Meninges:** protective coverings - **Cranial meninges:** Surrounding the brain - **Spinal meninges:** surrounding the spinal cord - **Dura mater:** dense irregular connective tissue; most superficial membrane - **Epidural space:** between vertebrae and dura matter; filled with connective, vascular, adipose tissues - **Arachnoid mater:** intermediate meninx; thinner and more elastic than dura mater - **Subdural Space:** between dura and arachnoid layers - **Pia mater:** deepest covering is well vascularized layer of connective tissue; adheres directly to surface of brain & spinal cord - **Subarachnoid space:** between pia mater and arachnoid mater; filled with cerebrospinal fluid ## **Spinal Cord - Spinal Meninges** - Vertebrae - Epidural space - Dura matter - Subdural Space - Arachnoid matter - Subarachnoid Space - Pia matter - Spinal cord ## **Brain - Cranial Meninges** - Cranium - Dura mater - Subdural Space - Arachnoid matter - Subarachnoid space - Pia matter - Brain ## **Thyroid & Parathyroid** - **Parathyroid:** four small masses of tissue lying on posterior side of thyroid gland made of chief cells - **Thyroid:** butterfly shaped inferior to larynx - **Thyroid follicles:** Spherical sacs composed of follicular cells that are cubodial to low columnar epithelia - **Follicular cells:** produce thyroxine (T4) and triiodothyronine (T3) hormones - **Colloid:** Space at center of follicle; precursor material of T3 and T4 hormones ## **Adrenal Gland** - **Location:** paired glands which sit atop the kidneys; each adrenal gland is triangular shaped and resembles a hat - **Zona fasciculata:** intermediate long straight columns; secrete glucocorticoids like cortisol - stress hormone - **Zona glomerusa:** deep; secretes mineralcorticoids like aldosterone - kidneys Sodium & potassium reabsorption - **Zona reticularis:** Secretes androgens - masculinizing hormones