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BIOL 2401

Fundamentals of Anatomy and Physiology

Mrs. Willie Grant

wgrant4@alamo.edu

(210) 643-8968

Chapter 17:The Special Senses

Chapter 18:The Endocrine System

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An Introduction to the Special Senses

Learning Outcomes

17-1 Describe the sensory organs of smell, trace the olfactory pathways to their destinations in the brain, and explain the physiological basis of olfactory discrimination.

17-2 Describe the sensory organs of taste, trace the gustatory pathways to their destinations in the brain, and explain the physiological basis of gustatory discrimination.

17-3 Identify the internal and accessory structures of the eye, and explain the functions of each.

17-4 Explain color and depth perception, describe how light stimulates the production of nerve impulses, and trace the visual pathways to their destinations in the brain.

17-5 Describe the structures of the external, middle, and internal ear, explain their roles in equilibrium and hearing, and trace the pathways for equilibrium and hearing to their destinations in the brain.

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An Introduction to the Endocrine System

Learning Outcomes

18-1 Explain the importance of intercellular communication, describe the mechanisms involved, and compare the modes of intercellular communication that occur in the endocrine and nervous systems.

18-2 Compare the cellular components of the endocrine system with those of other systems, contrast the major structural classes of hormones, and explain the general mechanisms of hormonal action on target organs.

18-3 Describe the location, hormones, and functions of the pituitary gland, and discuss the effects of abnormal pituitary hormone production.

18-4 Describe the location, hormones, and functions of the thyroid gland, and discuss the effects of abnormal thyroid hormone production.

18-5 Describe the location, hormone, and functions of the parathyroid glands, and discuss the effects of abnormal parathyroid hormone production.

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An Introduction to the Special Senses

Five Special Senses

1. Olfaction

2. Gustation

3. Vision

4. Equilibrium

5. Hearing

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Figure 17-1a The Olfactory Organs

Olfactoryepithelium

Olfactory Pathway to the Cerebrum

Olfactorynervefibers (N I)

Olfactorybulb

Olfactorytract

Centralnervoussystem

Superiornasal

concha

Cribriformplate

The olfactory organ onthe left side of the nasal septum

Smell (Olfaction)Olfaction Organs provide sense of smell. They are located in nasal cavity.

1 What is the life-span of an olfactory receptor?

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Taste Buds—associated with epithelial projections (lingual papillae) on superior surface of the tongueThree Types of Lingual Papillae Filiform papillae Fungiform papillae Circumvallate papillae

17-2 Taste (Gustation)

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Figure 17-4a External Features and Accessory Structures of the Eye

Gross and superficialanatomy of the accessory structures

Sclera

Lateral canthus

Eyelashes

Pupil

Palpebra

Palpebral fissure

Medial canthus

Lacrimal caruncle

Corneal limbus

(Vision)

Accessory Structures of the Eye (provide protection, lubrication and support)

Include: The palpebrae (eyelids) and the lacrimal apparatus

The palpebrae (eyelids)

The lacrimal apparatus

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Muscles of the Eye

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17-3 The Eye

Eyeball

Is hollow and divided into two cavities

1. Large posterior cavity

2. Smaller anterior cavity

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17-3 The Eye

Three Layers of the Eye

1. Outer fibrous layer

2. Intermediate vascular layer

3. Deep inner layer

2 What are the components of the fibrous tunic and vascular tunic?

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17-3 The Eye

The Inner Layer

Outer layer called pigmented part Inner called neural part (retina)

Contains visual receptors and associated neurons

Rods and cones are types of photoreceptors

Rods—Do not discriminate light colors/Highly sensitive to light

Cones—Provide color vision

Densely clustered in fovea, at center of macula

3 What the two types of photoreceptors, and how do their functions differ?

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The Chambers of the Eye

Aqueous Humor

Vitreous boody

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The Eye

Accommodation (shape of lens changes to focus image on retina)

Astigmatism

Condition where light passing through cornea and lens is not refracted properly

Visual image is distorted

Visual acuity

Clarity of vision

“Normal” rating is 20/20

Light Refraction (bending of light by retina and lens)

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4 What is presbyopia?

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17-4 Visual Physiology

The Visual Pathways

Begin at photoreceptors and ends at visual cortex of cerebral hemispheres

Message crosses two synapses before it heads toward brain

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17-5 The Ear

The External Ear

Auricle—surrounds entrance to external acoustic meatus and protects

opening of canal as well as provides directional sensitivity.

External acoustic meatus—ends at tympanic membrane (eardrum)

Tympanic membrane—is a thin, semitransparent sheet that separates

external ear from middle ear

Ceruminous glands—Integumentary glands along external acoustic

meatus that secretes waxy material (cerumen wich keeps foreign

objects out of tympanic membrane and slows growth of microorganisms

in external acoustic meatus.

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17-5 The Ear

The Middle Ear

Also called tympanic cavity

Communicates with nasopharynx via auditory tube

Permits equalization of pressures on either side of tympanic

membrane

Encloses and protects three auditory ossicles

1. Malleus (hammer)

2. Incus (anvil)

3. Stapes (stirrup)

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17-5 The Ear

The Internal Ear

Contains fluid called endolymph

Bony labyrinth surrounds and protects membranous labyrinth

Subdivided into:

Vestibule

Semicircular canals

Cochlea

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Figure 17-21 The Anatomy of the Ear

External Ear

Elastic cartilages

Auricle

External acousticmeatus

Tympanicmembrane

Tympaniccavity

Middle Ear

Auditory ossicles

Ovalwindow

Semicircular canals

Petrous part oftemporal bone

Facial nerve (N VII)

Cochlea

Vestibulocochlearnerve (N VIII)

Bony labyrinthof internal ear

Auditory tube

Tonasopharynx

VestibuleRoundwindow

Internal Ear

5 What structures separate the middle ear from the internal ear?

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PowerPoint® Lecture Presentations prepared byJason LaPresLone Star College—North Harris

18The Endocrine System

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An Introduction to the Endocrine System

The Endocrine System

Regulates long-term processes

Growth

Development

Reproduction

Uses chemical messengers to relay information and instructions between

cells

6 What is the basic difference between endocrine glands and exocrine glands?

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18-2 Hormones

Classes of Hormones

Hormones can be divided into three groups

1. Amino acid derivatives

2. Peptide hormones

3. Lipid derivatives

Secretion and Distribution of Hormones

Hormones circulate freely or travel bound to special carrier proteins

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18-2 Structural Classification of Hormones

http://resources.mhs.vic.edu.au/science/resources/hormones.htm

http://resources.mhs.vic.edu.au/science/resources/hormones.htm

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18-9 Endocrine Tissues of Other Systems

Many Organs of Other Body Systems Have Secondary Endocrine Functions

Intestines (digestive system)

Kidneys (urinary system)

Heart (cardiovascular system)

Thymus (lymphatic system and immunity)

Gonads (reproductive system)

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18-10 Hormone Interactions

Hormones Interact to Produce Coordinated Physiological Responses

When a cell receives instructions from two hormones at the same time, four outcomes are possible

1. Antagonistic effects - opposing

2. Synergistic effects - additive

3. Permissive effects - one hormone is necessary for another to produce effect

4. Integrative effects - hormones produce different and complementary results

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18-10 Hormone Interactions

Hormones Important to Growth

Growth hormone (GH)

Thyroid hormones

Insulin

PTH and calcitriol

Reproductive hormones

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18-10 Hormone Interactions

The Hormonal Responses to Stress

General Adaptation Syndrome (GAS)

Also called stress response

How body responds to stress-causing factors

Is divided into three phases

1. Alarm phase

2. Resistance phase

3. Exhaustion phase

9 What is the basic difference between the stress response and homeostasis?

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18-10 Hormone Interactions

The Effects of Hormones on Behavior

Hormone changes

Can alter intellectual capabilities, memory, learning, and emotional

states

Affect behavior when endocrine glands are over-secreting or under-

secreting

Aging and Hormone Production

Causes few functional changes

Decline in concentration of:

Growth hormone

Reproductive hormones