Lab 11THE SPECIAL SENSES AND THE ENDOCRINE GLANDS

Lab 11 Activities1. Identify structures of the eye on models and figures 2. Identify structures of the eye visible in a sheep eye

dissection3. Perform tests of visual acuity, near point

accommodation, astigmatism, and blind spot4. Identify structures of the ear on models and figures5. Identify endocrine glands on anatomical models and

know the hormones each secretes and their effects6. Identify histological structure of eye wall and retina on

microslides 7. Identify endocrine glands, their cells and other

structures visible on microslides (pituitary, thyroid/parathyroid, pancreas, adrenal gland, ovary, and testis and the hormones secreted by each)

The Special Senses• Special Photoreception (sight)

• Special Mechanoreception– Hearing– Static Equilibrium– Dynamic Equilibrium

• Special Chemoreception– Smell (Olfaction)– Taste

Surface Anatomy of the Eye

• Eyebrows divert sweat from the eyes and contribute to facial expressions

• Eyelids (palpebrae) blink to protect the eye from foreign objects and lubricate their surface

• Eyelashes detect and deter foreign objects

                                                                 

Extrinsic Eye Muscles

superior oblique

superior rectuslateral rectus

medial rectus

inferior rectus inferior obliqueOptic nerve

Internal Anatomy of the Eye

Tunics

surface of retina

Macula

Optic disc

Vasculature

Ophthalmoscope of Retina

Organization in the Retina

1. Pigmented Layer:– shields retina

from light scattering

2. Neural Layer:– photoreceptors

and several

types of interneurons

Micrograph of the Retina

Path of Light

Neurons of the Neural Layer• Photoreceptors:

– rods (for dim light)

– cones (3 colors [“blue,” “green” and “red”] for bright light)

• Bipolar cells connect interneurons

Neurons of the Neural Layer• Horizontal Cells

enhance contrast (light versus dark boundaries) and help differentiate colors

• Amacrine cells detect changes in the level of illumination

• Ganglion cells’ axons become the Optic Nerve

Retina 40x

Retina, 100x

Retina, 400x

External Ear• Pinna (Auricle):

focuses sound waves• External auditory

canal transmits sound waves• Ceruminous Glands

secrete cerumin (ear wax) to protect external auditory canal

• Tympanic membrane registers sound waves

Middle Ear & Auditory Tube• Three auditory ossicles (bones)

conduct vibrations of tympanic membrane to the oval window of the inner ear

• Pharyngotympanic tube (auditory tube or eustachian tube) connects to pharynx, equalizes air pressure on both side of the tympanic membrane

Middle Ear Ossicles• Malleus (hammer)• Incus (anvil) • Stapes (stirrup)

The Membranous Labyrinth

The Endocrine

System

ENDOCRINE GLANDSThe Endocrine Glands Produce Hormones Which Are Secreted Into the Blood Stream In Order To Locate Specific Target Tissues. Target Tissues Have Specific Hormone Receptors. Target Tissues Respond To Hormonal Commands In Specific Ways.

Anterior Lobe =Adenohypophysis

Posterior Lobe =Neurohypophysis

Pituitary Gland, 40x

each cell type secretes a different hormoneeach cell type secretes a different hormone

Hormones of the Pituitary Gland

• Anterior Lobe – Adenohypophysis– growth hormone (hGH)– thyroid stimulating hormone (TSH)– adrenocorticotropic hormone (ACTH)– prolactin– follicle stimulating hormone (FSH)– luteinizing hormone (LH) / interstitial cell stimulating

hormone (ICSH)

• Posterior Lobe – Neurohypophysis– oxytocin– vasopressin = antidiuretic hormone (ADH)

Thyroid Gland

ParathyroidGlands

Thyroid Gland

Trachea

Esophagus

Thyroid Thyroid

Thyroid, 40xThyroid, 40x

Follicles containing colloid (thyroxins)Follicles containing colloid (thyroxins)

Thyroid, 100xThyroid, 100x

Thyroid, 400xThyroid, 400xthyroglobulinthyroglobulin

TT33 = triiodothyronine = triiodothyronine

TT44 = tetraiodothyronine = thyroxine = tetraiodothyronine = thyroxine

Secretes calcitonin = thyrocalcitoninSecretes calcitonin = thyrocalcitonin

Thyroid & Parathyroid, 40xThyroid & Parathyroid, 40x

Thyroid & Parathyroid, 100x

Thyroid & Parathyroid, 400x

Parathyroid Hormone = Parathormone

Adrenal Gland, 40x

MedullaMedulla

CortexCortex

CortexCortex CortexCortex

CortexCortex

Adrenal Gland, 40xAdrenal Gland, 40x

cortexcortex

cortexcortex

Medulla: Norepinephrine and

Medulla: Norepinephrine and

Epinephrine (= Adrenalin)

Epinephrine (= Adrenalin)

(mineralocorticoids)(mineralocorticoids)

(glucocorticoids)(glucocorticoids)

(gonadocorticoids)(gonadocorticoids)

Pancreas

Pancreatic tissue, 40xPancreatic tissue, 40x(note Pacinian corpuscle)(note Pacinian corpuscle)

Pancreatic Islets, 100xPancreatic Islets, 100x

Acinar CellsAcinar Cellsendocrineendocrine exocrineexocrine

Pancreatic Islets, 100x(note Pacinian corpuscle)

Pancreatic Islet, 400x

Alpha cells - glucagonAlpha cells - glucagon Beta cells - insulin Beta cells - insulin

Ovary

Ovary, 40xOvary, 40x

Developing follicles Developing follicles secrete mostly secrete mostly estrogens and some estrogens and some progesteroneprogesterone

Ovary, 40xOvary, 40x

corpus luteum secretes mostly progesterone and some estrogen

TestisTestis

TestisTestis

Seminiferous Tubules

epididymis

TestisTestis

Testis

Androgens/Testosterone, etc.

Testis, 400xTestis, 400x

Cow Eye DissectionCow Eye Dissection

End Lab 11 End Lab 11 PresentationPresentation

Thyroid Gland

ThyroidColloid

Pancreas

Endocrine Pancreas

Ovary

Ovary