2025 Anatomy Exam 1 Flashcards
Lectures 1-4: Intro/Histology, Integumentary/Eye/Ear, Pulmonary, Cardiac/Great Vessels
Ways to Study Anatomy
Systemic (systematic) anatomy is organized according to functional systems: integumentary, musculoskeletal, nervous, circulatory, respiratory, digestive, urinary, reproductive and endocrine.
Regional anatomy is concerned with all systems found in a discrete part of the body: head and neck, back, thorax and abdomen, pelvis, upper and lower extremities.
Functional anatomy studies correlation between structure and function
Clinical anatomy emphasizes structure and function as it relates to the practice of medicine
Planes of the Body
Sagittal plane
1. a vertical line passing thru the body
2. this plane divides the body into right and left sections
3. median (mid) sagittal plane:
a. this is a vertical plane thru the center of the body
b. it divides the body into right and left sections
Coronal plane
1. a vertical plane that passes thru the body and divides the body into anterior and posterior sections
2. it is at a right angle to the median plane
Transverse plane
1. this is a horizontal plane passing thru the body and dividing it into superior and inferior sections.
Anatomical Position
Hand and Foot Terms
HAND
Palmar: used to describe the ‘anterior” surface of the hand
Dorsal: describes the “posterior” side of the hand
FOOT
Plantar: describes the “inferior” surface of the foot; the surface that is not visible when standing
Dorsal: describes the “superior” surface of the foot; the surface that is visible when standing
Other Anatomical Terms
Proximal: describes an area that is closest to a point of reference
When used in general terms it means closest to the bodies center
Distal: describes an area that is farthest from a point of reference
When used in general terms it means furthest to the bodies center
Superficial: describes a point that is closest to the surface of the body
Deep: describes a point that is farthest from the surface of the body
Internal and external:
describes the distance of a structure from the center of an organ
Ipsilateral:
denotes (of) the same side
Contralateral:
denotes (on) the opposite side
Supine (supination):
lying on the back
Prone (pronation):
lying on the ventral surface (face down)
Rostral:
Situated near the front of the body
Latin for beak (rooster). Sometimes used interchangeably with anterior
Often used in neurological terms
Caudal:
Situated near the bottom or end of an organism
Latin for tail. Sometimes used interchangeably with posterior
Often used in neurological terms (spine)
Cephalic: Toward the head
Greek for “head”
Sometimes used interchangeably with superior
Used often in neurology; cephalically
Ventral: Denoting something is anterior to another structure
Typically, only used when the anatomical structure is easily divided into two parts and has an opposite dorsal structure
Ex. Ventral horn vs Dorsal horn
Flexion/Extension
Usually occur in midsagittal or parasagittal planes
Flexion brings primitively ventral surfaces together
Bending arm at elbow
Extension – movement away from ventral surface
Straitening leg at knee joint
Plantar flexion – downward flexion (true flexion) of foot at ankle joint
Dorsiflextion – upward flexion (extension) of foot at ankle joint
Abduction/Adduction
Usually occur in midcoronal plane
Abduction (lateral flexion) – movement away from median, away from middle finger, away from 2nd toe.
Radial deviation – abduction of hand at wrist joint
Adduction – movement toward median, toward middle finger, toward 2nd toe
Ulnar deviation – adduction of hand at wrist joint
Medial/Lateral Rotation
Usually occurs about vertical axis
Medial rotation – movement of ventral surface toward median
Bringing flexed arm across the chest
Lateral rotation – movement of ventral surface away from median
Directing head toward one side
Pronation/Supination
Generally refers to the hands and the action of the wrist:
Pronation is medial rotation so palm faces posteriorly
Supination is lateral rotation so palm faces anteriorly
Holding a cup of soup
Inversion/Eversion
Generally refers to the foot
Inversion rotates planar surface inward
Eversion rotates planar surface laterally
Specific Movements
Intorsion / extorsion of eye: rotation about axis through pupil with top of the eye as reference
Opposition / reposition of thumb – unique human characteristic; rotation about resultant axis
Circumduction – combined movement involving two pairs of movement: flexion / extension + abduction / adduction
Body Cavities
Two sets of internal body cavities
Closed to environment
Provide different degrees of protection to organs
Dorsal body cavity
Protects nervous system
Two subdivisions:
Cranial cavity
Encases brain
Vertebral cavity
Encases spinal cord
Ventral body cavity
Houses internal organs (viscera)
Two subdivisions (separated by diaphragm):
Thoracic cavity
Two pleural cavities
Each houses a lung
Mediastinum
Contains pericardial cavity, esophagus, trachea, and thymus
Also contains the thoracic duct, cardiac, and phrenic nerves
Surrounds thoracic organs
Pericardial cavity
Encloses heart
Abdominopelvic cavity
Abdominopelvic cavity subdivisions
Abdominal cavity
Contains stomach, intestines, spleen, and liver
Pelvic cavity
Contains urinary bladder, reproductive organs, and rectum
Membranes in Abdominopelvic Cavity
Serous membrane or serosa
Thin, double-layered membranes
Parietal serosa lines internal body cavity walls
Visceral serosa covers internal organs (viscera)
Layers separated by slit-like cavity filled with serous fluid
Fluid secreted by both layers of membrane
Protects and provides lubrication (antifriction)
Pericardium
Serous Membrane
Named for specific cavity and organs with which associated
Each has parietal and visceral layers
Pericardium
Heart
Pleurae
Lungs
Peritoneum
Abdominopelvic cavity
9 Abdominopelvic Regions
Abdominal Quadrants
Other Body Cavities
Exposed to environment
Oral and digestive cavities
Gastrointestinal tract involves everything from mouth to anus
Nasal cavity
Upper respiratory tract: Superior larynx to sinuses/middle ear
Lower respiratory tract: Inferior larynx to alveoli
Orbital cavities
Middle ear cavities
Not exposed to environment
Synovial cavities = Joint fluid
Levels of Structural Organization
Chemical
Atoms and molecules; and organelles
Cellular
Cells
Tissue
Groups of similar cells
Organ
Contains two or more types of functional tissues
Organ System
Organs that work closely together
Organismal
All organ systems
Histology Overview
There are over 75 trillion cells in the body
There are approximately 200 types of cells
All cells can be placed into one of the four tissue categories
Epithelial tissue
Connective tissue
Muscular tissue
Neural tissue
Epithelial Tissue
Epithelial Tissue Characteristics
Cellularity
Cells are bound close together
No intercellular space
Polarity
Have an exposed apical surface
Have an attached basal surface
Surfaces are structurally and functionally different
Polarity is the term that is in reference to this structural and functional difference
Attachment
Basal layer is attached to the basal lamina
Avascularity
Do not contain blood vessels
Arranged in sheets
Composed of one or more layers of cells
Regeneration
Cells are continuously replaced via cell reproduction
Functions of Epithelial Tissue
Provides physical protection
Protection from abrasion, dehydration, and destruction
Controls permeability
Provides sensation
Produces secretions
Specialization of Epithelial Cells
Microvilli
For absorption and secretion
Found on apical surface of cells of the urinary and digestive tracts
Increases surface area
Stereocilia
Long microvilli, commonly found in the inner ear and male reproductive tract
Ciliated epithelium
Moves substances over the apical surface
Found lining the respiratory tract
Integrity of Epithelium
Three factors involved in maintenance
Intercellular connections
Attachment to the Basal Lamina
The plasmalemma attaches to the basal lamina
Consists of typically two layers
Clear layer
Dense layer
Basal lamina in turn attaches to underlying connective tissue
Epithelial maintenance and renewal is self-perpetuated
Classification of Epithelia Tissue
Simple
Epithelium has only one layer of cells
Nuclei are approximately at the same level within each cell
Found in protected areas such as the internal compartments of the body
Stratified
Epithelium has two or more layers of cells
Found in areas where there are mechanical or chemical stresses
Epithelial Tissue Cells
Squamous cells
Thin, flat cells / “squished” nuclei
Cuboidal cells
Cube-shaped cells / centered, round nucleus
Columnar cells
Longer than they are wide / nucleus near the base
Transitional cells
Mixture of cells / nuclei appear to be scattered
Simple Squamous Epithelium
Consists of very delicate cells
Location
Lining body cavities, the heart, the blood vessels
Function
Reduces friction
Absorbs and secretes material
Stratified Squamous Epithelium
Location
Surface of skin
Lines mouth, esophagus, anus, vagina
Function
Protection against abrasion, pathogens, and chemicals
Simple Cuboidal Epithelium
Location
Thyroid gland, ducts, kidney tubules
Function
Secretion, absorption
Very limited protection
Stratified Cuboidal Epithelium
This type of cells is rare
Location
Ducts of sweat glands
Function
Secretion, absorption
Simple Columnar Epithelium
Location
Lining stomach, intestines, gallbladder, uterine tubes, and collecting ducts of the kidneys
Function
Secretion, absorption, protection
Stratified Columnar Epithelium
Location
Pharynx, epiglottis, anus, mammary glands, salivary glands, and urethra
Function
Protection
Pseudostratified Ciliated Columnar Epithelium
Nuclei situated at different levels
Location
Nasal cavity, trachea, bronchi
Function
Protection, secretion
Transitional Epithelium
Consists of many layers
Consists of a combination of cuboidal and “oddly” shaped cells
Location
Urinary bladder, renal pelvis, and ureters
Function
Ability to stretch extensively
Glandular Epithelia
Many epithelia contain gland cells
Glands are classified based on:
Type of secretion released
Structure of the gland
Mode of secretion
Types of glands
Exocrine
Secretions travel through ducts to the epithelial surface
Categories
Serous glands: secrete watery fluids rich in enzymes
Mucous glands: secrete glycoproteins (mucins) that absorb water to produce mucus
Mixed exocrine glands: contain both serous and mucous secretions
Endocrine
Secretions enter the blood or lymph
Categories
Release their secretions by exocytosis
Secretions are called hormones
Gland Structures
Unicellular
Secrete mucins… 2 kinds
Goblet
Found among columnar epithelium of small and large intestines
Mucous
Found among pseudostratified ciliated columnar epithelium of the trachea
Multicellular
Secrete mucins
Produces secretory sheets
Produce exocrine secretions
Consists of a portion that produces the secretion
Consists of a portion that carries the secretion to the epithelial surface
Produce endocrine secretions
Connective Tissue
All connective tissues have three main components
Specialized cells
Extracellular protein fibers
Matrix
The matrix is the collective term for the extracellular component of any connective tissue that is made of protein fibers and the ground substance
Functions of Connective Tissue
Establishing the structural framework of the body
Transporting fluid and dissolved materials
Protecting organs
Supporting, surrounding, and connecting other tissues
Storing energy
Defending the body from microorganisms
Classifications of Connective Tissue
Connective tissue proper
Has a matrix of fibers (loose fibers and dense fibers)
Fluid connective tissue
Has a matrix of liquid (blood and lymph)
Supporting connective tissue
Has a matrix consisting of a gel or a solid (cartilage and bone)
Connective Tissue Proper (Fixed Cells)
Two classes of connective tissue proper cells
Fixed cells
Mesenchymal cells
Fibroblasts
Fibrocytes
Fixed macrophages
Adipocytes
Melanocytes
Wandering cells
Connective Tissue Proper (Wandering Cells)
Fixed cells
Wandering cells
Free macrophages (monocytes)
Mast cells
Lymphocytes
Neutrophils
Eosinophils
Connective Tissue Proper Fibers
Three types of fibers associated with connective tissue
Collagen fibers
Reticular fibers
Elastic fibers
Connective Tissue Fibers (Loose and Dense)
Loose fibers
Areolar tissue
Adipose tissue
Reticular tissue
Dense fibers
Dense regular
Dense irregular
Elastic
Areolar Connective Tissue
Acts a flexible, cushion connecting different organs and tissues surrounding them with a loose network of loosely arranged collagen and elastic fibers
Adipose Connective Tissue
Location
Hypodermis
Buttocks, surrounds organs
Function
Cushion
Insulation
Matrix
Fibers
Reticular Connective Tissue
Location
Liver, spleen, kidney, lymph nodes, tonsils, appendix, bone marrow
Function
Supporting framework
Matrix
Fibers
Dense Regular Connective Tissue
Location
Tendons, aponeuroses, ligaments, elastic tissue
Function
Tendons: connect muscle to bone
Aponeuroses: connect muscle to muscle or covers entire muscle
Ligaments: connect bone to bone
Elastic: stabilizes the vertebrae
Matrix
Fibers
Elastic Connective Tissue
Dense
Dense Irregular Connective Tissue
Location
Nerve and muscle sheaths
Function
Provides strength
Matrix
Fibers
Fluid Connective Tissue (Blood)
Location: circulatory system
Erythrocytes
Transport oxygen and carbon dioxide
Leukocytes
Fight infections
Platelets
Blood clotting
Matrix
Liquid (plasma)
Fluid Connective Tissue
Lymph
Location
Lymphatic system
Lymphocytes
Develop into T cells and B cells (for example)
Function
Involved with the immune system
Supporting Connective Tissue
Provide a strong framework that supports rest of body
Cartilage
Gel matrix made of chondroitin sulfate
Cells reside in lacunae
Bone
Solid matrix made of calcium phosphate
Cells reside in lacunae
Supporting Connective Tissue (Cartilage)
Types of Cartilage:
Hyaline cartilage
Location
Connection between ribs and sternum
Connection within the joints of the elbow and knee
Tracheal cartilage rings
Function
Flexible support
Reduces friction
Matrix
Gel
Elastic cartilage
Location
Auricle of the ear
Epiglottis
Auditory tube
Function
Flexible support
Matrix
Gel
Fibrous cartilage
Location
Pads within the knee joints
Pads between the spinal vertebrae
Pubic symphysis
Function
Resists compression
Absorbs shock
Matrix
Gel
Supporting Connective Tissue (Bone)
Location
Skeletal system
Function
Support and strength
Matrix
Solid (lamellae)
Made of osteons
Osteons consist of:
Central canal
Osteocytes
Lacunae
Canaliculi
Matrix of lamellae
Membranes
Epithelia and connective tissue combine to form membranes
Each membrane consists of:
Sheet of epithelial cells
An underlying connective tissue
Four types of membranes
Mucous
Serous
Cutaneous
Synovial
Mucous Membranes
Line digestive, respiratory, reproductive, and urinary tracts
Form a barrier that resists pathogen entry
Keep the epithelial surfaces moist
The connection of the epithelium with underlying tissue is called lamina propria
Provide support for blood vessels and nerves
Serous Membranes
Line the body cavities
Consist of a parietal and a visceral layer
Three types of serous membranes
Pleura: lines the lungs
Peritoneum: lines the peritoneal cavity
Pericardium: lines the heart
Cutaneous Membranes
Makes up the skin
Consists of keratinized stratified squamous epithelium
Thick and waterproof
Synovial Membranes
Lines the joint cavities
Produces synovial fluid that reduces friction within the joints
Different than the other membranes
No basal lamina or reticular lamina
Has gaps between cells
Cells are derived from macrophages and fibroblasts
Fascia
Connective tissue creates the internal framework of the body
Layers of connective tissue connect organs with the rest of the body
Layers of connective tissue are called fascia
Superficial fascia
Deep fascia
Subserous fascia
Muscle Tissue
Have the ability to contract and relax
Three types of muscle cells
Skeletal muscle
Smooth muscle
Cardiac muscle
Cells are different than “typical” cells
Cytoplasm is called sarcoplasm
Plasmalemma is called a sarcolemma
Skeletal Muscle
Sometimes referred to as skeletal muscle fibers
Multinucleated: Nuclei lie just under the sarcolemma
Incapable of cell reproduction
Myosatellite cells can reproduce and therefore muscle repair is possible
Have a striped appearance under the microscope
Voluntarily moves the skeleton
Smooth Muscle
Found:
Base of hair follicles, in the walls of blood vessels, lining the urinary bladder, within respiratory, circulatory, digestive, and reproductive tracts
Is capable of cell reproduction
Has tapered ends
Nonstriated
Involuntary contraction
Cardiac Muscle
Found only associated with the heart
Each cell has just one nucleus
Cells connected by intercalated discs
Pulsating contractions
Also called striated involuntary muscle
Nervous Tissue
Neural Tissue
Specialized to conduct electrical signals through the body
Two types of neural cells
Neurons are the cells that actually transmit the impulse
Neuroglia are the supporting cells of the neural tissue; these cells protect the neurons
Longest cells in the body
Incapable of cell reproduction
Consists of:
Soma, axon, dendrite
Layers of Skin
Cellular Arrangement Type
The Epidermis
5 Layers
Protection – Against microbes, chemicals, and UV radiation
Water resistant – Keratin in the external layer of the epidermis function. Controls skin permeability.
Synthesizes vitamin D3 (cholecalciferol)
Sensory receptors present for touch, pressure, temperature, and pain, particularly the latter two.
Stratum Corneum
Most external/superficial layer of skin
Composed of flattened keratin filled cells – keratinization
Keratinocytes take 15-30 days to travel from the basal layer to the stratum corneum
Technically composed of dead cells (keratinocytes)
Stratum Luciderm
Only seen in thick skin
Superficial to the stratum granulosum but deep to the stratum corneum
Appears as a clear or glassy layer – luciderm means clear layer
Have no nucleus, the cells are converting to almost all keratin protein
Stratum Granulosum
Superficial to the stratum spinosum and deep to the stratum luciderm
Most superficial layer of the skin that still contain a nucleus
As the name denotes, they contain granules, these granules contain the primary proteins of the epidermis
Keratohyalin
Keratin
The keratohyalin creates the water-resistant barrier but results in all layers superficial to it the inability to transport nutrients and oxygen thus resulting in their death.
Stratum Spinosum
Superficial to the stratum basale and deep to the stratum granulosum.
Keratinocytes grow and maturate here as they move externally from the stratum basale where they originated (aka the skin nursery)
Langerhan cells (Dendritic cells) and melanocytes
Organized in stratified squamous epithelium
Langerhan (Dendritic) Cells
The primary antigen presenting cell (APC)
Transports antigens from the skin to the lymph nodes and spleen
Stratum Basale
The deepest layer of skin and where all epidermal cells originate.
Sometimes referred to as the stratum germinativum because cells germinate there
The stem cells (basal cells) are anchored to the basal lamina, a thin layer of collagenous connective tissue of which the basal cells adhere to as they maturate.
These basal cells become keratinocytes as they differentiate.
Contain: Melanocytes
Produce melanin, which gives humans skin pigmentation and determines the color of the irises and absorbs UV radiation.
Merkel cells
Sensitive to mechanical pressure and when release chemicals that stimulate sensory nerve endings
The Dermis
Deep to the epidermis and superficial to the hypodermis
Can be thought of as the metropolitan center of the skin
Location of:
Blood supply
Hair follicles
Specialized skin sensors
Apocrine glands
Exocrine glands
Layers of Dermis
Papillary layer
Loose connective tissue
Contains capillaries and axons
Reticular layer
Deep to the papillary layer
Irregular, dense connective tissue
Surrounds blood vessels, hair follicles, nerves and glands
Langer Lines or Skin Tension Lines
Langer lines or lines of cleavage (also known as tension lines) are collagenous fiber bundles that are aligned in specific patterns throughout the body depending on the stress placed on the skin with normal movement and gravity.
Mostly consisting of type I and type III collagen.
Very important surgically
Accessory Structures of the Dermis: Hair Follicle
Located every where in the body except the palms, soles, lips, and portions of the external genitalia.
≈ 5 million hairs on the human body, only 2% on the head.
They are non-living structures composed of the protein keratin that form in an organ known as the hair follicle.
Hair papillae = blood supply and innervation
Hair bulb = Epithelial cells that surround the hair papillae
Hair matrix = Epithelial layer that produces keratin
Hair Structure
Medulla = Soft keratin
Cortex = Hard keratin
Hair Function
Head = UV protection, insulation, and physical protection.
Nares/eye lashes/external auditory canal = Physical barrier to large particles
Sensory = Early-warning system to help prevent injury
Arrector pili = Smooth muscle tissue extending from the papillary layer of the dermis to the connective tissue sheath around the hair follicle
Stimulated by sympathetic endocrine-nervous system (fight, flight or freeze)
Cold
Hair pigmentation determined by melanocytes in the hair papillae
Two Types of Adult Hairs
Vellus = Fine hair which covers most of the body
Terminal Hair = Thicker and more deeply pigmented. Eyebrows, eyelashes, pubic hair, axillary hair
Sebaceous Gland (An exocrine gland)
Oil glands; coats the hair follicle/shaft
Lubricate dermis with oily, lipid substance
Contains biochemicals for inhibiting bacterial growth
Other Exocrine Glands
Overall functions:
Assist in thermoregulation
Excrete waste
Lubricate dermis
Apocrine Sweat Glands
Produces viscous secretion
Strongly influenced by hormones (think puberty)
Nutrient source for bacteria
Pheromone production
Special Apocrine Glands:
Mammary = Milk production
Ceruminous = Ear wax
Eccrine Sweat Glands
Produce thin secretions, mostly water
Controlled by nervous system
Crucial in thermoregulation
Widespread throughout the body, roughly 3 million in the adult
Palms and soles have the most per sq cm
Pure sweat glands are called merocrine sweat glands; high volume producers
Body Location of Two Types of Sweat Glands
Accessory Neural Structures of Dermis
Free Nerve Endings
Nociceptors = Pain sensors, think of the word noxious
Information sent to the lateral spinothalamic tract
Afferent and usually unmyelinated
Also detect heat (thermal energy)
Extend to the stratum basale
Merkel Discs
Mechanoreceptors that sense light touch
Information sent to the ventral spinothalamic tract
Found in the palms, soles, mucosa, and nail beds
Extend into the stratum basale
Meissner’s Corpuscles (tactile corpuscles)
Large, encapsulated mechanoreceptors
Extend to the stratum basale
Detect light touch, movement, and low-frequency vibration
Information sent to the dorsal columns of the spinal cord
Found in areas of high sensitivity: eyelids, fingertips, lips, nipples, and external genitalia.
Ruffini Corpuscles (Bulbous corpuscles)
Located in the dermis and sensitive to pressure, heat, and skin stretching
Information sent to the dorsal columns of the spinal cord
Capsule surrounds a core of collagen fibers that are continuous with the dermis. This assures it detects stretching
Located throughout the body
Pacinian Corpuscles (Lamellar corpuscles)
Large, encapsulated mechanoreceptors for deep touch and high-frequency vibrations
Information sent to the dorsal columns of the spinal cord
Located deeper in the dermis, almost in the hypodermis so it is isolated and thus only to detect deeper sensations
Located throughout the body
Krause’s End Bulb
Thought to be a thermoreceptor for detecting cold
Overall Picture of Accessory Neural Structures of Dermis: Special Sensors
Dermal Blood Supply
Divided into papillary plexus and cutaneous plexus
Capillary loops of the papillary plexus extend the most superficially and terminate just outside the epidermis
Crucial in thermoregulation
Precapillary sphincters are innervated by sympathetic nerve fibers and epinephrine/norepinephrine will contract the sphincter thus reducing blood flow to the skin for the sake of more vital internal organs.
Think of flight or fight; turning white as a ghost.
The epidermis gets a little oxygen from the capillary loops but much of their oxygen supply is directly from the ambient air; same case for the cornea of the eye.
Papillary Sphinctors
The Hypodermis
Contains the subcutaneous fat with many blood vessels.
Provides insulation and protection
Allows some mobility of the skin
AKA subcutaneous tissue (used a lot in medicine); loose connective and adipose tissue
Most internal or deep of the dermal layers.
Nails
Nail body
External component, composed of keratin
Bounded by nail grooves and folds
Eponychium extends over body at nail root
Hyponychium is the free end of the nail bed
Paronychium is the lateral skin fold on both sides of the nail
Function of the nails are to protect the distal phalanx of the finger or toe it is associated with.
Nail Matrix = Contains specialized epithelial cells to produce the nail root
Cuticle is another name for the eponychium
Underlying blood vessels give the nail its pink appearance, which becomes pale as you move toward the eponychium, because the blood vessels are becoming obscured. This is called the lunula.
Anatomy of the External Ear
Auricle
External acoustic meatus
Tympanic membrane
Ceruminous glands
Anatomy of the External Ear (2nd Version)
Auricle
External acoustic meatus
Tympanic membrane
Ceruminous glands
3 Parts of the Ear
Tympanic Membrane
Middle Ear
Tympanic cavity
Auditory ossicles
Malleus, incus, and stapes
Auditory tube (pharyngotympanic tube)
The Ossicles
Malleus
Incus
Stapes
Eustachian Tube
Equalizes pressure in middle ear
Allows fluid to drain from the middle ear
Positioned horizontally in children
Results in stasis of fluid
Inner Ear
Consists Of:
Receptors
Membranous labyrinth (within the bony labyrinth)
Bony labyrinth
Vestibule
Semicircular canals
Cochlea
Utricle
Saccule
Hearing and Balance Structures
Cross Section Semicircular Canal
Hearing Mechanism
Inner Ear - Vestibular Complex
The vestibular complex and equilibrium
Part of inner ear that provides equilibrium sensations by detecting rotation, gravity, and acceleration
Consists of:
Semicircular canals
Utricle
Saccule
The semicircular canals
Each semicircular canal encases a duct
The beginning of each duct is the ampulla
Within each ampulla is a cristae with hair cells
Each hair cell contains a kinocilium and stereocilia
These are embedded in gelatinous material called the cupula
The movement of the body causes movement of fluid in the canal, which in turn causes movement ofthe cupula and hair cells, which the brain detects
The utricle and saccule
The utricle and saccule are connected to the ampulla and to each other and to the fluid within the cochlea
Hair cells of the utricle and saccule are in clusters called maculae
Hair cells are embedded in gelatinous material consisting of statoconia (calcium carbonate crystals)
Gelatinous material and statoconia collectively are called an otolith
When you rotate your head:
The endolymph in the semicircular canals begins to move
This causes the bending of the kinocilium and stereocilia
This bending causes depolarization of the associated sensory nerve
When you rotate your head to the right, the hair cells are bending to the left (due to movement of the endolymph)
When you move in a circle and then stop abruptly, the endolymph moves back and forth causing the hair cells to bend back and forth resulting in confusing signals, thus dizziness
When you move up or down (elevator movement):
Otoliths rest on top of the maculae
When moving upward, the otoliths press down on the macular surface
When moving downward, the otoliths lift off the macular surface
When you tilt side to side:
When tilting to one side, the otoliths shift to one side of the macular surface
Crista Ampularis
Head in Neutral vs Head Tilt for Balance
Balance and Cranial Nerves
The Ear and Hearing - The Cochlea
The Cochlea
Consists of “snail-shaped” spirals
Spirals coil around a central area called the modiolus
Within the modiolus are sensory neurons
The sensory neurons are associated with CN VIII
Organ of Corti
Each spiral consists of three layers
Scala vestibuli (vestibular duct): consists of perilymph
Scala tympani (tympanic duct): consists of perilymph
Scala media (cochlear duct): consists of endolymph / this layer is between the scala vestibuli and scala tympani
The scala vestibuli and scala tympani are connected at the apical end of the cochlea
Sense organs rest on the basilar membrane within the scala media
The Organ of Corti
Also known as the spiral organ
Rests on the basilar membrane between the scala media and the scala tympani
Hair cells are in contact with an overlying tectorial membrane
This membrane is attached to the lining of the scala media
Sound waves ultimately cause a distortion of the tectorial membrane, thus stimulating the organ of Corti
Auditory Pathways
Sound waves enter the external acoustic meatus
The tympanic membrane vibrates
Causes the vibration of the ossicles
The stapes vibrates against the oval window of the scala tympani
Perilymph begins to move
As the perilymph moves:
Pressure is put on the scala media
This pressure distorts the hair cells of the organ of Corti
This distortion depolarizes the neurons
Nerve signals are sent to the brain via CN VIII
Structures of Organ of Corti
Cochlea to Brain
Accessory Structures of the Eye
Accessory structures of the eye
Palpebrae (eyelids)
Medial and lateral canthus (connect the eyelids at the corners of the eye)
Palpebral fissure (area between the eyelids)
Eyelashes (contain root hair plexus, which triggers the blinking reflex)
Conjunctiva (epithelial lining of the eyelids)
Glands: glands of Zeis, tarsal glands, lacrimal gland, lacrimal caruncle
Eye Muscles and Accessory
Extrinsic Eye Muscles
The 6 extrinsic muscles move the eye in many directions
Each muscle is associated with one primary action
Superior rectus- CN III
Inferior rectus- CN III
Medial rectus- CN III
Lateral rectus- CN VI
Superior oblique- CN IV
Inferior oblique- CN III
“LR6(SO4)3”
Extraocular Movement
SO = down and out
IO = up and out
SR = up
IR = down
LR = out
MR = in
Eye Movement Chart
Eye Need to Know
Sclera
Cornea
Pupil
Iris
Lens
Anterior cavity
Posterior cavity
Three tunics:
(1) fibrous tunic, (2) vascular tunic, and (3) neural tunic
Retina
Fibrous Tunic
Outer Layer
Makes up the sclera and cornea
Provides some degree of protection
Provides attachment sites for extra-ocular muscles
The cornea is modified sclera
Vascular Tunic
Middle Layer
Consists of blood vessels, lymphatics, and intrinsic eye muscles
Regulates the amount of light entering the eye
Secretes and reabsorbs aqueous fluid (aqueous humor)
Controls the shape of the lens
Includes
Iris
Consists of blood vessels, pigment, and smooth muscles
The pigment creates the color of the eye
The smooth muscles contract to change the diameter of the pupil
Ciliary body
The ciliary bodies consist of ciliary muscles connected to suspensory ligaments, which are connected to the lens
Choroid
Highly vascularized
The innermost portion of the choroid attaches to the outermost portion of the retina
The Retina
Cavities and Chambers of the Eye
Anterior cavity
Anterior chamber
Posterior chamber
Filled with fluid called aqueous fluid
Posterior cavity
Vitreous chamber
Filled with fluid called vitreous fluid
Vision Pathway
Light waves pass through the cornea
Pass through the anterior chamber
Pass through the pupil
Pass through the posterior chamber
Pass through the lens
The lens focuses the image on some part of the retina
This creates a depolarization of the neural cells
Signal is transmitted to the brain via CN II
The retina
There are rods and cones all over the retina
100% cones in the fovea centralis area
The best color vision is when an object is focused on the fovea centralis
0% rods or cones in the optic disc area
If an object is focused on this area, vision does not occur
Also known as the “blind spot”
The cones require light to be stimulated (that’s why we see color)
At night (still has to be at least a small amount of light), the cones deactivate, and the rods begin to be activated (that’s why we can see at night but we can’t determine color at night)
Optic Chiasm
Respiratory System
Larynx Upper for this class???
Respiratory Epithelium
Pseudostratified ciliated columnar cells
Except for the pharynx, smaller bronchi, and alveoli
Stratified squamous cells
Nonkeratinized
Found in the pharynx
Mucus-producing cells
Found in the nasal cavity
Found in the lower respiratory tract
Pseudostratified ciliated columnar cells
Cilia move mucus in an upward manner (mucociliary escalator) to pharynx so debris can be coughed out or swallowed
Stratified squamous cells
Provide protection against abrasion
Mucous cells
Produce mucus so inhaled debris will get stuck and not enter the lungs
Pathway of Air
Air enters the external nares or nostrils
Passes by the nasal vestibule
Area supported by paired alar and lateral cartilages
Enters the nasal cavity
Separated into left and right portions by nasal septum
Bony portion composed of fused vomer and perpendicular plate of ethmoid
Anterior portion composed of hyaline cartilage
Air flows in and around the nasal conchae
Inferior, middle, and superior conchae
As air swirls around the conchae, debris gets stuck in the mucus
As air swirls around the conchae, the air warms and humidifies before entering the trachea
Air enters the internal nares
Air enters the nasopharynx area
Pharynx
Larynx
A cylinder whose cartilaginous walls are stabilized by ligaments or skeletal muscles or both
Begins at the level of vertebra C3 to C5
Ends at the level of vertebra C6 to C7
Cartilages of the Larynx
Thyroid cartilage
Contains the laryngeal prominence
Hyaline cartilage
Cricoid cartilage
Encircles the trachea
Hyaline cartilage
Epiglottis
Closes over the glottis during swallowing of food
Elastic cartilage
Paired Laryngeal Cartilages
Some play a role in the opening and closing of the glottis
Consists of:
Arytenoid cartilages (hyaline cartilage)
Corniculate cartilages (hyaline cartilage)
Cuneiform cartilages (elastic cartilage)
Glottis
Laryngeal Ligaments
Vestibular and vocal ligaments
Extend between the thyroid cartilage and the arytenoids
Vestibular ligaments lie within the vestibular folds
The inelastic vestibular folds are also known as false vocal cords and play no role in sound production
The vocal ligaments are associated with the delicate vocal folds
The elastic vocal folds are also known as the true vocal cords and play a role in sound production
Glottis Open and Closed
Trachea
Characteristics of the trachea
11 cm long and 2.5 cm diameter
Bifurcates at the carina into the right and left bronchi at T5
Contains 15–20 tracheal cartilages
Composed of hyaline cartilage
Each cartilage ring is actually C-shaped, not a complete ring
Connecting one cartilage ring to another are annular ligaments
The lining consists of:
Mucosa or mucous membrane
Respiratory epithelia
Lamina propria
Submucosa
The posterior side of the cartilage ring is the trachealis muscle
This muscle allows for constriction and dilation of the trachea
The Lungs
Structure of the lungs
The apex points superiorly and the base inferiorly
Lobes and Fissures of the Lungs
The right lung has three lobes
Superior, middle, and inferior lobes
Contains a horizontal fissure and an oblique fissure
The left lung has two lobes
Superior and inferior lobes
Contains the oblique fissure
Left lung has a cardiac notch
Main Bronchi
The main bronchi branch numerous times once inside the lungs
Each main bronchus divides to form:
Lobar bronchi (also called secondary bronchi)
Lobar bronchi branch to form segmental bronchi (tertiary bronchi)
Each segmental bronchus goes to a specific lung area called a bronchopulmonary segment
Lobar bronchi and segmental bronchi have hyaline cartilage plates to provide support
Lobar Bronchi
The lobar bronchi divide to form segmental bronchi
Segmental bronchi deliver air to the bronchopulmonary segments
The right lung has 10 segmental bronchi and therefore 10 bronchopulmonary segments
The left lung has 9 segmental bronchi and therefore 9 bronchopulmonary segments
Alveolar Ducts and Alveoli
Respiratory bronchioles are attached to alveolar ducts
Alveolar ducts end at alveolar sacs
Each lung has about 150 million alveoli
Extensive network of capillaries surrounds each alveolus
Capillaries drop off carbon dioxide and pick up oxygen
Elastic tissue surrounds each alveolus
Maintains the shape and position of each alveolus during inhalation and exhalation
Blood Air Barrier
The Alveolus and the Blood Air Barrier
The cells associated with alveoli
The lining consists of a single layer of squamous cells
These are called type I alveolar cells
Type II alveolar cells are scattered among the type I alveolar cells
Type II alveolar cells secrete surfactant
Surfactant prevents alveolar collapse
Alveolar macrophages wander around phagocytizing particulate matter
Gas exchange occurs at the blood air barrier
Alveolar cell layer (type I and type II alveolar cells)
Capillary endothelium
Fused basement membrane between alveolar cells and capillary endothelium
Gas exchange
Carbon dioxide leaves the capillaries and enters the alveolar sacs
Oxygen leaves the alveolar sacs and enters the capillaries
Respiration Muscles
Primary respiratory muscles
Diaphragm
Contracts (lowers) to cause inhalation
Relaxes (raises) to cause exhalation
External intercostals
Elevate the ribs to aid in inhalation
Accessory respiratory muscles
Muscles aiding inhalation include:
Serratus anterior
Scalenes
Pectoralis minor
Sternocleidomastoid
Exhalation Muscles
PASSIVE EVENT!
Accessory respiratory muscles
Muscles aiding exhalation include:
Internal intercostals
Transversus thoracis
External oblique
Internal oblique
Rectus abdominis
The Heart
Pulmonary verse Systemic Circuit
Layers of the Heart
Endocardium: Inner lining of myocardium (valves)
Myocardium: Contractile muscle tissue
Epicardium: outermost layer made of visceral (inner) serous layer of pericardium
Pericardial cavity: potential space, some serous fluid
Pericardium: 2 layers = 1 fibrous (protective) outer + 1 serous (epicardium)
Intercalated Disks
Cardiac cells have specialized cell-to-cell junctions
The plasma membranes of two adjacent cardiac cells are bound together by desmosomes
The intercalated discs bind the myofibrils of adjacent cells together
Cardiac muscle cells are connected by gap junctions
Ions move directly from one cell to another creating a direct, electrical connection that allows all the muscle cells to form a functional syncytium (contract as one unit)
Orientation of Heart
The heart lies slightly to the left of midsagittal plane
Located in the mediastinum
The base is the superior border of the heart
The apex is the inferior portion of the heart
The right border is formed by only the right atrium
The inferior border is formed by the right ventricle
The heart is rotated slightly toward the left
The anterior surface consists of the right atrium, right ventricle, and the left ventricle
The posterior surface consists of the left atrium and a small portion of right atrium
The diaphragmatic surface is composed of the right and left ventricles
Sulci Grooves
The four chambers of the heart can be identified by sulci (grooves) on the external surface
Interatrial groove separates the left and right atria
Coronary sulcus separates the atria and the ventricles
Anterior interventricular sulcus separates the left and right ventricles
Posterior interventricular sulcus also separates the left and right ventricles
Heart Septums
A frontal section of the heart reveals:
Left and right atria separated by the interatrial septum
Left and right ventricles separated by the interventricular septum
The atrioventricular valves are formed from folds of endocardium
The atrioventricular valves are situated between the atria and the ventricles
Right Atrium
Receives oxygen-poor venous blood via the superior vena cava, inferior vena cava, and coronary sinus
Coronary sinus enters the posterior side of the right atrium
Contains pectinate muscles
Anterior wall and auricle
Interatrial septum contains the fossa ovalis
fetal remnant of the foramen ovale that allowed fetal blood to bypass the lungs
Right Ventricle
Receives oxygen-poor blood from the right atrium
Blood enters the right ventricle by passing through the right atrioventricular valve
Also called right AV valve or tricuspid valve
Blood leaves the right ventricle by passing through the pulmonary valve
Also called pulmonary semilunar valve
Leads to the pulmonary trunk, then to the right and left pulmonary arteries
The right AV valve is connected to papillary muscles via chordae tendineae
There are three fibrous flaps or cusps and three papillary muscles
Each of the three cusps is connected by the chordae tendineae to separate papillary muscles
Papillary muscles and chordae tendineae prevent valve inversion when the ventricles contract
Trabeculae carneae and Moderator Band
The Right Ventricle
The internal surface of the right ventricle consists of:
Trabeculae carneae = Muscular ridges
Moderator band
Found only in the right ventricle
Muscular band that extends from the interventricular septum to the ventricular wall
Prevents overexpansion of the thin-walled right ventricle
Left Ventricle
Has the thickest wall
Needed for strong contractions to pump blood throughout the entire systemic circuit
Compare to the right ventricle, which has a thin wall since it only pumps blood through the pulmonary circuit
Does not have a moderator band
Prominent trabeculae carneae
The left AV valve has chordae tendineae connecting to two cusps and to two papillary muscles
Blood leaves the left ventricle by passing through the aortic valve
Also called aortic semilunar valve
Blood enters the ascending aorta
Blood then travels to the aortic arch and then down the descending aorta and to all body parts (systemic)
Cadaver Heart
Right Coronary Artery
Major branches off the right coronary artery:
Atrial branches
Right marginal branch
Posterior interventricular branch
Conducting system branches
Left Coronary Artery
Major branches off the left coronary artery
Anterior interventricular branch
Branches that lead to the posterior interventricular branch called anastomoses
Circumflex branch
Branches to form the left marginal branch
Branches to form the posterior left ventricular branch
Left Coronary Artery (Posterior)
Coronary Veins
Drain cardiac venous blood ultimately into the right atrium
Main coronary veins
Great cardiac vein
Delivers blood to the coronary sinus
Middle cardiac vein
Delivers blood to the coronary sinus
Coronary sinus
Drains directly into the posterior aspect of the right atrium
Main coronary veins
Posterior vein of the left ventricle
Parallels the posterior left ventricular branch
Small cardiac vein
Parallels the right coronary artery
Anterior cardiac veins
Branches from the right ventricle cardiac cells
Coronary Veins (Posterior)
Cardiac Cycle
Nodes
Sinoatrial node (SA node)
Located in the posterior wall of the right atrium near the entrance of the superior vena cava
Also called the cardiac pacemaker
Pacemaker cells in the SA node automatically generate 80–100 action potentials per minute
Bradycardia—slower-than-normal heart rate
Tachycardia—faster-than-normal heart rate
Atrioventricular node (AV node)
Sits within the floor of the right atrium
Movement of Electrical Signals
Autonomic Control on Heart
The SA node sets the heart rate but can be altered
Impulses from the autonomic nervous system modify the pacemaker activity
Nerves associated with the ANS innervate the:
SA node
AV node
Cardiac cells
Smooth muscles in the cardiac blood vessels
The effects of NE and ACh on nodal tissue
Norepinephrine from the sympathetic division of the ANS causes:
An increase in the heart rate
An increase in the force of contractions
Acetylcholine from the parasympathetic division of the ANS causes:
A decrease in the heart rate
A decrease in the force of contractions
Cardiac centers in the medulla oblongata modify heart rate
Stimulation of cardioacceleratory center:
activates sympathetic neurons
Heart rate increases
Stimulation of cardioinhibitory center:
activates parasympathetic neurons
Vagus (N X) is involved
Heart rate decreases
