anatomy lecture 3 exam
less light in
pupillary constriction
more light in
pupillary dilation
Our bodies are constantly exposed to sensory
information called?
stimuli
Our conscious awareness to these stimuli is called
sensation
Stimuli are detected by ___ in our body
receptors
receptors - temperature, pain, touch, stretch, and pressure
general senses
receptors – gustation (taste), olfaction, vision, equilibrium, and audition (hearing)
special senses
structures that detect stimuli and monitor changes in either the external or internal body
receptors
General sense receptors are distributed
throughout the?
skin and organs
Special sense receptors are housed in complex?
organs in the head
3 criteria used to describe receptors
1. stimulus origin
2. receptor distribution
3. modality of stimulus
3 types of stimulus origin receptors
1. exteroceptors
2. interoceptors
3. proprioceptors
found in skin or mucous membranes such as nasal and oral cavities, vagina, and anal canal
exteroceptors
found in the walls of viscera; detecting stretching, oxygen depravation, temperature, and pressure
interoceptors
found in muscles, tendons and joints; detecting body and limb movement, muscles contraction/stretching
proprioceptors
3 types of receptors based on distribution
1. somatic receptors
2. visceral receptors
3. special senses
found within the body wall; they include receptors for chemicals, temperature, pain, touch, proprioception, and pressure
somatic receptors
found within the walls of the viscera; they respond to chemicals, temperature, and pressure
visceral receptors
located only in the head; gustation, olfaction, vision, equilibrium, and hearing
special senses
6 major classes of receptors based on the stimulating agent
1. chemoreceptors
2. thermoreceptors
3. photoreceptors
4. mechanoreceptors
5. baroreceptors
6. nociceptors
detect specific dissolved molecules
chemoreceptors
detect changes in temperature
thermoreceptors
detect changes in light
photoreceptors
detect physical deformation due to touch, pressure, vibration, and stretch
mechanoreceptors
detect pressure changes within body structures
baroreceptors
detect tissue damage and pain
nociceptors
mechanoreceptors that react to touch, pressure, temp, and vibration stimuli
• Most numerous type of receptor
• Located in the dermis and subcutaneous layer of the skin
tactile receptors
taste receptors housed in specialized organs termed taste buds
gustatory cells
sense of taste
gustation
stem cells
basal cells
Each gustatory cell has a dendritic ending called ____ or taste hair.
gustatory microvillus
taste hair extends through
taste pore
sense of smell
olfaction
Inside the nasal cavity are paired ______
consisting of several components
olfactory organs
olfactory epithelium - consists of three distinct cell types:
1. olfactory receptor cells
2. supporting cells
3. basal cells
At the apical end of the olfactory receptors cells are
nerve endings called ____ that project through the mucous covering the olfactory epithelium
olfactory hairs
capable of detecting light, color, and movement
photoreceptors
Three principal layers form the wall of the eye
fibrous tunic
vascular tunic
retina
composed of cornea and sclera
fibrous tunic
Anterior part, transparent, avascular
cornea
makes up the majority of the fibrous tunic; considered the “white” of the eye and allows for the attachment of the extrinsic eye muscles to the eye
sclera
contains a vast network of capillaries, which supply nutrients and oxygen to the retina
choroid
composed of choroid, ciliary body, and iris
vascular tunic
Composed of ciliary muscles and ciliary processes; ciliary muscles contract or relax shaping of the lens to focus incoming light onto the retina
ciliary body
Pigmented part of the eye. Black hole is called
the pupil, which allows light to pass on to the retina
iris
Internal layer of the eye wall composed of two layers
retina
attached to the choroid; absorbs light energy that passes through the retina and provides photoreceptors with vitamin A
pigmented layer
houses photoreceptors and other associated neurons
neural layer
• Area of retina that contains the highest proportion of cones and almost no rods
• Sharpest area of vision
fovea centralis
"Blind spot” on retina
• Located where ganglion cell axons exit retina to form optic nerve (CN II)
• Lacksphotoreceptors
optic disc
between the lens and the cornea--Aqueous humour
anterior cavity
posterior to the lens and anterior to the retina--Vitreous humour
posterior cavity
3 layers of the neural layer
photoreceptor layer
bipolar cells
ganglion cells
outermost layer composed of rods (dim) and cones (color)
photoreceptor layer
synapse with photoreceptors and ganglion cells
bipolar cells
innermost layer of the retina; axons of these cells leave the retina and form the optic nerve
ganglion cells
The ear is divided into three distinct anatomic regions:
1. external ear
2. middle ear
3. inner ear
Skin covered, funnel-shaped,elastic cartilage supported structure called the
auricle
Auricle leads to a bony tube called the external
acoustic meatus, which ends at the
tympanic membrane
3 auditory ossicles:
1. malleus
2. incus
3. stapes
attached to tympanic membrane; articulates with incus
malleus
middle of the three bones; articulates with stapes
incus
fits into the oval window on cochlea
stapes
Located in spaces within the petrous portion of the temporal bone
inner ear and bony labyrinth
spaces in petrous portion of the temporal bone are called
bony labyrinth
fluid filled tubes
1. vestibular complex
2. cochlea
detects balance and rotation
vestibular complex
hearing organ
cochlea
• Utricle and Saccule
• Macula
vestibule
Ampulla
Crista ampullaris
semicircular canals
Contains hair cells that are sensory receptors for balance/equilibrium
maculae structure
On their apical surface of each hair cell are many stiff microvilli called
stereocilia
one long cilium called
kinocilium
gelatinous mass is known as the
otolithic membrane
Within each semicircular canal is an expanded region called the
ampulla
The ampulla contains an elevated region called the
crista ampullaris
The stereo cilia/kinocilia of the hair cells embed into an overlying gelatinous dome called the
cupula
organ for hearing
cochlea
cochlea contains 3 chambers:
1. cochlear duct - medial
2. scala vestibuli - superior
3. scala tympani - inferior
spiral organ consists of thick sensory epithelium that includes hair cells and supporting cells on the
basilar membrane
Thespiralorganislocatedwithinthecochlearductand
detects movement of endolymph
spiral organ
The stereocilia of hair cells project into an overlying mass
called the
tectorial membrane
The spinal cord and its attached spinal nerves serve two important functions:
1. A pathway for sensory and motor impulses
2. Responsible for reflexes, which are the quickest reactions to a stimulus
The spinal cord is partitioned into an ____
matter region and an ____ matter region:
inner gray, outer white
dendrites and cell bodies of neurons, unmyelinated axons, and glial cells
gray matter
myelinated axons
white matter
Centrally located in spinal cord
• Sectioned shape resembles butterfly
gray matter
subdivided into:
1. anterior horns
2. lateral horns
3. posterior horns
4. gray commissure
are ductless organs secrete their molecular products (hormones) into the bloodstream
endocrine glands
All endocrine organs have an extensive distribution of many
many
blood vessels
Endocrine glands produce informational molecules
called
hormones
Hormones can only affect cells (target cells) or organs (target organs) that have ____ for a specific hormone.
receptors
the study of the structural components of the endocrine system, the hormones they produce, and the effects of these hormones on target organs
endocrinology
3 major classes of hormones based on their chemical structure:
1. peptide hormones
2. steroid hormones
3. biogenic amines
growth hormone
peptide hormones
estrogen/testosterone
steroid hormones
thyroid hormone
biogenic amines
Hormone secretion is regulated by a self-
adjusting mechanism called a
feedback loop
2 types of feedback loop
1. negative
2. postive
in a negative feedback loop, a ___ starts the process
stimulus
A hormone is ____ in response to elevated stimululs
secreted
The hormone secreted ____ the stimulus
counteracts
In this type of loop, the stimulus does not produce an opposite and counteracting effect like a negative feedback loop
positive feedback loop
the ____ is the interface between the nervous system and the endocrine system
hypothalamus
hypothalamus controls most endocrine functions including:
1. release of regulatory hormones that control the anterior pituitary
2. secretes oxytocin and antidiruetic hormones from posterior pituitary
3. controls the stimulation and secretion activities of the adrenal medulla
Located just inferior to the hypothalamus
• Connected to the hypothalamus by a thin stalk called the infundibulum
• Divided into anterior and posterior lobes
pituitary gland
Anterior pituitary hormone production is controlled by ___ secreted by the hypothalamus
regulatory hormones
These regulatory hormones travel to the anterior pituitary through a blood vessel network called the
hypothalamo-hypophyseal portal system
7 major hormones secreted from the anterior pituitary:
1. Thyroid stimulating hormone (TSH)
2. Prolactin (PRL)
3. Adrenocorticotropin hormone (ACTH) 4. Growth hormone (GH)
5. Follicle stimulating hormone (FSH)
6. Lutenizing hormone (LH)
7. Melanocyte-stimulating hormone (MSH)
Low GH from birth
Pituitary Dwarfism
Excess GH from birth
Pituitary Gigantism
Excess GH in adulthood
Acromegaly
comprised of the 2 major regions, pars nervose and infundibular stalk
Posterior Pituitary
neural lobe
pars nervosa
connection
infundibular stalk
Neural connection between the hypothalamus and the posterior pituitary is the
hypothalamo-hypophyseal tract
Located just inferior to the thyroid cartilage and anterior to the trachea
• Butterfly shape with right and left lobes connected by a midline isthmus
• Secretes thyroid hormones
thyroid gland
Functional unit of the thyroid gland
• Comprised of simple cuboidal cells that produce an iodinated glycoprotein called thyroglobulin (TGB)
• Digestion of TBG releases thyroid hormones
thyroid follicle
Excess TH secretion
Hyperthyroidism
an autoimmune disorder where an antibody auto-activates TSH receptor on thyroid gland. Causes exophthalmos
graves disease
Decreased TH secretion
Hypothyroidism
Small glands (usually four) embedded on the posterior surface of the thyroid gland
• Secretes parathyroid hormone (PTH) that helps regulate serum calcium
parathyroid glands
Paired glands anchored on the superior border of the
two kidneys
adrenal glands
Divided functionally into an outer adrenal cortex and
an inner adrenal medulla
adrenal gland structure
Located between the duodenum and spleen and posterior to the stomach
• Bothan exocrine(ducted)and endocrine(ductless) gland
pancreas
produce alkaline pancreatic secretions into ducts
pancreatic acini
The remaining 1–2% of cells are small clusters of endocrine cells called
pancreatic islets
Comprised of four different types of endocrine
cells each secreting a different hormone:
pancreatic islets
secrete glucagon
alpha cells
secrete insulin
beta cells
secrete somatostatin
delta cells
secrete pancreatic polypeptide
F cells
a lifelong (chronic) disease in which there are high levels of sugar in the blood
can be caused by too little insulin, resistance to insulin, or both
diabetes
In this disease, the body makes little or no insulin. Daily injections of insulin are needed.
type 1 diabetes
makes up most diabetes cases. It most often occurs in adulthood. However, because of high obesity rates, teens and young adults are now being diagnosed with it. Many people with ____ do not know they have it.
type 2 diabetes
A distribution and collection system to main homeostasis
circulatory
Distribute oxygen, collection and removal of CO2
respiration
Absorbed by digestive system • Stored – Liver, fat, bone
nutrition
Eliminated by urinary, respiratory, integumentary
• Excess H2O, minerals, metabolic wastes
collection of waste products
Antigens, antibodies, leukocytes, platelets
protection
Transportation of oxygen and carbon dioxide as well as nutrients and waste products
• Regulation of body temperature, pH, and fluid volume
• Protection by mounting an immune response and the
production of antibodies
• 7-8% body weight; 5L (1.3gal) in 140lb person
blood
represent 44% of total blood volume
erythrocytes
represents about 1% of total blood volume
buffy coat
represents 55% of total blood volume
plasma
92% of serum. Acts as solvent in which formed elements, solutes, and wastes are suspended
water
7% of serum
plasma proteins
4 major types of plasma proteins
1. albumin
2. globulins
3. fibrinogen
4. regulatory
blood viscosity and transports hormones/fatty acids
albumin
transport lipids and antibodies
Globulins
blood clotting
fibrinogen
enzymes and peptide hormones
regulatory
1% of plasma
solutes
Na, K, Ca, Cl, Fe
electrolytes
amino acids, glucose, cholesterol, vitamins
nutrients
O2, CO2
respiratory gases
lactic acid, urea, ammonia
wastes
the process of erythrocyte production
erythropoiesis
During maturation, all organelles within the erythrocyte, including the nucleus ____
degenerate
biconcave discs contain
hemoglobin
Every erythrocyte contains 280 million molecules of a
red-pigmented protein called ____
hemoglobin
Hemoglobin is capable of reversibly transporting
____ in the blood
oxygen and carbon dioxide
Each hemoglobin molecule can bind a combination of ___ oxygen molecules – 1 at each heme. CO2 binds the globin chain.
4
possess a nucleus and organelles
• Initiate immune response and defend the body against pathogens
• 1.5 to 3 times larger than erythrocytes.
Capable squeezing out of blood vessels, diapedesis, and entering a tissue.
leukocytes
Irregular membrane-enclosed cellular fragments that
represent shed cytoplasm from cells in the red bone
marrow called
megakaryocytes
platelets are involved in the
clotting of blood