Anat Exam 1

Polarity (epithelial tissue)

Differences in s/f between apical and basal surfaces

Basal surface

Cell surface attached to underlying tissue

Apical surface

Exposed surface of the cell

Basement membrane

Anchors cells to underlying tissue

Sits below basal surface

Epithelial tissue functions

Protection

Selective permeability (Diffusion, Absorption)

Secretion

Sensation

Surface parallel transport

Epithelia cell structural/functional features

Highly cellular

Avascular

Regenerative

Polar

Avascular

No blood vessels

Cilia

Extensions off apical surface that beat to move fluids and trapped particles across epithelial surface (surface parallel transport)

Microvilli

Extensions that increase the SA of the apical surface to increase absorption

Tight junction

Holds cells together so there is no extracellular space

Prevents substances from moving between cells (forces them to go through cells → selective barrier)

Adhering junction

Acts like a belt to hold cells together

For increased tissue support and stability

Desmosome

Holds cells together like a button to provide tissue support and stability

Gap junction

Forms intercellular pathway between adjacent cell membranes to facilitate movement of small molecules between their cytoplasm

3 shapes of epithelial cells

Squamous

Cuboidal

Columnar

Types of cell layers in epithelial tissues

Simple

Stratified

Pseudostratified

Simple squamous epithelium s/f

Single layer of flat cells

Allows materials to quickly pass through simple diffusion/filtration

Simple squamous location

Alveoli

Air Sacs

Places where substances need to pass quickly

Simple cuboidal s/f

Single layer of cuboidal cells (square)

May have microvilli

Secretion and absorption

Simple cuboidal location

Certain glands

Kidney tubules

Where there is space for intracellular processing of absorbed substances but isn’t too thick

Simple columnar s/f

Single layer of cells that are taller than they are wide

May have microvilli

Absorption and secretion

Simple columnar location

Digestive tract

Ample space for intracellular processing of absorbed substances

Pseudostratified columnar s/f

Single layer of cells of different shapes and sizes

Only some reach the apical surface

May contain cilia

Surface parallel transport and mucous secretion

Pseudostratified columnar location

Trachea

Places where no smooth muscle to move substances through a tract

Stratified squamous s/f

Multiple layers of flat, thin cells

Flatten as they reach apical surface

Protection

Stratified squamous location

Skin, esophagus

In places exposed to physical and chemical wear and tear

Transitional epithelium s/f

Layers of cells that stretch with organ distension

Allows urinary organs to expand and stretch

Transitional epithelium location

Bladder

Ureters

Urethra

Goblet cell

Unicellular exocrine gland between (pseudo)stratified columnar cells of mucous membranes

Secrete mucin → mixed with water to become mucous

Endocrine gland

Ductless gland that releases hormones directly into surrounding tissues and bloodstream

Exocrine gland

Secretions leave through a duct that opens directly or indirectly to a surface

Connecting tissue functions

Support and connect other tissues

Protection

Defense

Transport

Energy storage

Connective tissue proper fiber types

Collagen

Elastic

Reticular

Primary cell type of connective tissue proper

Fibroblast

Secretes ground substance and protein fibers in ECM

Collagen fibers

Flexible

Great tensile strength

Resist stretching

Elastic fibers

Contain elastin

Returns to original shape after being stretched/compressed

Reticular fibers

Most abundant in reticular tissue in soft organs (liver, spleen)

Anchor and provide structural support to organ while providing space for blood and cells to move through structure

Loos connective tissue types

Areolar

Adipose

Reticular

Areolar connective tissue

Little specialization

All cell types and fibers distributed in random, web-like fashion

Underlies most epithelia

Fills spaces between muscle fibers, surrounds blood and lymph vessels, and supports abdominal cavity organs

Adipose tissue

Contains adipocytes with little ECM

Rapid storage and mobilization of lipids

Reticular tissue

Mesh-like supportive framework for soft organs like lymphatic tissue

Like a scaffolding that also allows space for blood and cells to pass through

Produce reticular fibers

Dense connective tissue types

Dense regular

Dense irregular

Elastic

Dense regular connective tissue

Fibers parallel

Enhances tensile strength and stretch resistance in the only direction of the fiber orientations

Ex. tendons

Dense irregular connective tissue

Direction of collagen fibers is random

Greater strength in all directions and less strength in one direction

Ex. dermis

Elastic connective tissue

Elastin and collagen that allow tissues to return to original length after stretching

Ex. vocal chords, walls of large blood vessels

Excitability

Can respond to a stimulus

Contractility

Can contract and shorten the length of the fiber

Extensibility

Can stretch or extend beyond its resting length

Elasticity

Can return to its original length when relaxed

Skeletal muscle myocyte shape

Large, long, cylindrical

What muscle types are striated

Cardiac and skeletal

Carcinoma

Malignant tumor of epithelia

Adenocarcinoma

Malignant tumor from glandular epithelial cells

Metaplasia

Normal epithelia from one area replaced by another form not typical for that region

Found in Barrett’s esophagus, acid reflux, etc

Necrosis/Apoptosis

Cell death

Neoplasia

Abnormal proliferation

Cardiac muscle shaped

Small, short, branched

Smooth muscle shape

Small spindle-shaped (tapered edges like a football)

Which muscle type(s) are voluntary?

Skeletal

Which muscle type(s) are involuntary?

Cardiac

Smooth

Cardiac muscle location

Heart wall

Smooth muscle location

Walls of many internal organs and passageways

Digestive, respiratory, blood vessels, eye, skin

Skeletal muscle location

Muscles that are for movement

External sphincters

Cardiac muscle function

Circulate blood

Which muscle types are connected by intercalated disks and gap junctions

Cardiac

Which muscle types are capable of cell division to produce more cells

Smooth muscle

Smooth muscle function

Move food/urine/reproductive secretions through their respective systems

Control diameter of blood vessels, respiratory tracts, iris

Skeletal muscle function

Movement/stabilization of skeleton

Guard entrances/exits of the digestive, respiratory, and urinary systems

Heat production

Protects internal organs

Skeletal muscle key functions

Produce movement

Maintain posture and stabilize joints

Generate heat

Protect internal organs

Epimysium

Sheath of dense, irregular connective tissue surrounding each muscle

Perimysium

Sheath of connective tissue surrounding each fascicle

Endomysium

Sheath of connective tissue surrounding each individual muscle fiber

Layers of skeletal muscle

Myofibrils are surrounded by sarcolemma to create muscle fibers

Muscle fibers with satellite cells and endomysium make up fascicles

Fascicles surrounded by perimysium make up skeletal muscle

Skeletal muscle is surrounded by epimysium

Myofilaments

Myosin and actin

Sarcomere

Unique repetitive grouping of actin and myosin

Functional unit of muscle fiber

NMJ

Where motor neuron meets muscle fiber

How many motor neurons innervate a muscle fiber

Only 1

How many muscle fibers can a motor neuron innervate

Several

Motor unit

Group of muscle fibers innervated by a single motor neuron

How does the size of the motor unit determine function

Small motor unit permits fine motor control (fingers, eyes)

Large motor units are concerned with gross movements (thigs, back)

All-or-none principle

All muscle fibers in a motor unit will contract when a motor neuron is stimulated

How does number of motor units recruited correlate to the strength of the contraction

More motor units leads to stronger contraction

SO muscle fibers characteristics

Contract relatively slowly

Aerobic

Less power but greater endurance

What are SO fibers for

Maintaining posture

Producing isometric contractions

Stabilizing bones and joints

Small movements that happen often but do not require large amounts of energy

FG fiber characteristics

Fast contractions

Primarily use glucose

Fatigue quickly

FG muscle fiber are for

Rapid, forceful contraction

Hypertrophy

Increase in size of the muscle

Atrophy

Decrease in muscle mass

CNS components

Brain

Spinal Cord

PNS components

All nervous tissue outside of the brain and SC

Types of cells in NS

Neurons

Neuroglia (glial cells)

Neuron function

Transmit info through the body via electrochemical signals

Synapse

Gap between a neuron and its target

Neural cell body

Includes most of cytoplasm, organelles, and nucleus

Thinking part of neuron

Dendrite

Branches that receive most input from other neurons and carry it to the cell body

Usually highly branched

Axon

Fiber that emerges from cell body and projects to target cells

Propagates nerve impulse

Pseudounipolar neurons

Axon that emerges from cell body but splits to that the axon can extend along a very long distance

One end has dendrites and the other end has the axon that forms synaptic connections with the target

Exclusively sensory neurons

Bipolar neurons

Two processes, which extend opposite to each other (one is dendrite, one is axon)

Not very common

Found in olfactory epithelium

Multipolar neurons

Most common neurons

One axon and 2+ more dendrites

Glial cell role

Cells that support neurons

Astrocyte characteristics

Processes extending from main cell body

Extend to neurons and blood vessels