Anatomy exam 1

What characteristics do all myocytes share?

Excitability (respond to stimulus), contractility (contract and shorten length of fiber), extensibility (stretch and extend beyond resting length), elasticity (return to original length when relaxed)

What are the skeletal muscle functions

Maintain posture, stabilize joints, generate heat, protect internal organs

What are the different types of muscle tissue

Skeletal (moves bones/joints), cardiac, smooth

What is unique about cardiac muscle

Found in heart. Smaller and shorter than skeletal. Contains intercalated discs w/ gap junctions. Cannot repair itself or generate new cells

What is unique about smooth muscle

There are no striations and way shorter than skeletal muscle fibers. These cells can divide.

What are the 3 skeletal muscle connective tissues?

Epimysium (sheath of dense, irregular CT surrounds each muscle), perimysium (sheath of CT surrounding individual fascicle), endomysium (sheath surrounding individual muscle fiber)

What is the order of skeletal muscles?

Skeletal muscle → Fascicles → Muscle fiber → Myofibrils → Myofilaments

Which glial cells are in the CNS?

Astrocytes (most abundant), microglia (smallest/least abundant), oligodendrocytes (myelinate axons), ependymal cells (filter blood to make cerebrospinal fluid)

Function of astrocytes

• Regulate environment around neurons

• Contribute to blood-brain barrier

• CT of brain → filling spaces

• Form scar tissue of brain

• Regulate inflammatory response to damage

• Synapse formation and neuronal growth

• Propagate calcium signals involved w/ memory

Function of microglia

• Immune cells of brain

• Phagocytize debris

Glial cells of the PNS

Schwann cells (myelinate axons), satellite cells (surround cell bodies of neurons to protect them)

How do Schwann cells myelinate axons?

Only one Schwann cell myelinate one portion of axon

Neuromuscular junction

Where motor neuron meets muscle fiber

Motor unit

single motor neuron and muscle fibers it controls

All or none principle

All muscle fibers in motor unit contracts completely or not at all

What are types of skeletal muscle fibers

Slow oxidative fibers (aerobic, endurance), fast glycolytic fibers (anaerobic, instantaneous power)

What are the 4 main fascicle arrangements

Parallel, convergent, pennate (unipennate, bipennate, multipennate), circular

Collection of cell bodies terminology: CNS vs PNS

CNS: nucleus, center ; PNS: Ganglion

Collection of axons terminology: CNS vs PNS

CNS: tract, column ; PNS: nerve

What are the different gliomas

Astrocytomas, oligodendroglioma, mixed gliomas

How many pairs of nerves are in the cervical region of spinal cord?

8 (c1-c8)

What is the cervical enlargement?

Houses neurons that innervate muscles of upper extremities

What does cervical enlargement do?

It controls fine motor control (like fingers)

How many pairs of nerves are in the thoracic region of the spinal cord?

12 (t1-t12)

How many pairs of nerves are in the lumbar region of the spinal cord?

5 (l1-l5)

What is the lumbar enlargement?

It innervates muscles of lower extremity

How is the motor control of lumbar enlargement different from cervical enlargement?

It has less fine motor control

How many pairs of nerves are in the sacral region of the spinal cord?

5 (s1-s5)

How many pairs of nerves are in the coccygeal region of the spinal cord?

1

What is the cauda equina?

It is a long bundle of nerves at bottom of spinal cord

What is the conus medularis?

It is the most inferior (lowest) part of the spinal cord

Where is the spinal cord located?

In the vertebral foramen

What is important about the vertebral foramen?

It is an opening in the spine that allows spinal nerves and blood vessels to pass the spinal cord and rest of the body

What type of processing are the dorsal/posterior horns of grey matter for?

Sensory processing

What type of processing are ventral/anterior horns of grey matter for?

Motor signals to skeletal muscles

What is important about the lateral horn?

Only in the thoracic region. Helps control automatic, involuntary body functions

Where are upper motor neurons?

Originate in brain and descend through spinal cord

What do upper motor neurons do?

Excite or inhibit lower motor neuron

Where are lower motor neurons?

Originate in anterior horn of spinal cord

What do lower motor neurons do?

If lower motor neuron is excited, muscle will contract

What are ventral roots?

Axons of motor neurons carrying info away from spinal cord

What are dorsal roots?

Axons of sensory neurons carrying info to CNS from periphery

What is the dorsal root ganglion?

Contains cell bodies for pseudounipolar sensory neurons

What do dorsal and ventral roots merge to form?

Spinal nerve

What is dorsal ramus?

Carries sensory and motor info from or to posterior trunk

What is the ventral ramus?

Carries sensory and motor info from or to extremities and anterior trunk

Where are proprioceptors located?

Skeletal muscles, tendons, joints

What is the function of proprioceptors

Muscle tension, send input on body movements to CNS

What is the reflex arc

Rapid, automatic, involuntary reaction of muscles to stimulus

Which side is the reflex arc?

Can be ipsilateral or contralateral

What are golgi tendon organs

Nerve endings located within tendon near a muscle-tendon junction

What is the golgi tendon reflex and what is it an example of?

It monitors tension within the tendons and it is example of polysynaptic reflex

What is a monosynaptic reflex and what is an example of it

It monitors muscle spindles and the stretch of the muscle and speed of stretch. An example is the patellar tendon reflex

What is a polysynaptic withdrawal reflex

Painful stimulus sensory info is sent to spinal cord where interneurons receive stimulus and stimulate motor neurons to direct flexor muscles to contract.

What happens to extensor muscles during polysynaptic withdrawal reflex?

They are inhibited so traumatized body part can quickly withdraw from harm

What does anterior artery of spinal cord supply?

It is a single artery that supplies anterior 2/3 of spinal cord

What does posterior artery of spinal cord supply?

There are 2 arteries that supply posterior 1/3 of spinal cord

What is Amyotrophic Lateral Sclerosis (ALS)

It is a motor neuron disease, both upper and lower motor neurons involved, it is a slow progression of weakness and atrophy with fasciculations

How is ALS diagnosed?

Electromyography

What does a tactile corpsucle do?

Responds to light touch

What does a lamellated corpuscle do?

Responds to deep pressure

What do tactile discs do?

Light-tough receptors

What do bulbous corpuscles do?

Deep pressure and skin distortion detection

What is a root hair plexus?

Sensory neurons connected to each hair follicle

What are free nerve endings?

Pain and temperature receptors

What is the epidermis?

It is the avascular part of skin and has either 4 or 5 layers of skin

What are keratinocytes?

They are cells that manufactures and store keratin and they are found in epidermis

What is keratin

Intracellular protein that gives hair, nails, skin hardness and water resistance

What is the stratum basale

It is the deepest epidermal layer and attaches epidermis to basal lamina

What are 2 cells found in stratum basale

Tactile cells (abundant in hands and feet) and melanocytes (produce melanin and absorb UV light)

What are dermal papillae

They increase strength of connection between epidermis and dermis in stratum basale

What is the stratum spinosum?

It is the second deepest layer that consists of 8-10 layers of living keratinocytes.

What cells are found in stratum spinosum

Dendritic cells: function as macrophages

What is the stratum granulosum

It is the middle layer where living keratinocytes are (have nucleus). Here, they synthesize keratin and prevent water loss

What is stratum lucidum

Composed of few layers of densely packed, flattened dead keratinocytes and is ONLY present in thick skin. Serves as additional water barrier

What is stratum corneum?

Most superficial layer, mutiple layers of dead keratinocytes and it is a durable water-resistant layer that protects underlying layers

How often is the stratum corneum replaced?

Every 4 weeks

What is the dermis?

It is the thickest, vascular layer of skin that has 2 layers: papillary and reticular

What is the papillary layer of the dermis

It is the most superficial layer and is made of loose areolar connective tissue that contains phagocytes, lymphatic capillaries, and nerve fibers

What is important about papillary layer

It is where dermal papillae and epidermal ridges interlock

What is the reticular layer of dermis

It is made of dense, irregular connective tissue and it is 70-80% thickness of the dermis

What are striae

Stretch marks where skin is overstretched is reticular layer

What are cleavage lines

Collagen and elastin fibers organized thin parallel bundles to resist stress in reticular layer

What does hair do and what is it made of

Serves to protect, sensory input, thermoregulation, communication and made of dead keratinized cells

What are arrector pilli?

smooth muscle that contracts in response to nerve signals from sympathetic NS (found in hair)

Where is hair derived from

Epidermis

What is the hypodermis

It connects skin to fibrous tissue of bones and muscles and contains apidose tissue. It is NOT part of the integument

What are the hypodermis functions

Stores energy, thermal insulation

What do nails do

Protect tips of fingers and toes

Where are nails from

Modification of stratum corneum

What is the eccrine sweat gland

It produces hypotonic sweat for thermoregulation

Is sweat hyper or hypo tonic in eccrine sweat glands

Hypotonic

What is the apocrine sweat gland

It is found in densely hairy areas (armpit) and sweat induces organic compounds that make sweat thicker

What are unencapsulated tactile receptors and what are examples

Not wrapped in myelin

Ex: free nerve endings, tactile discs, root hair plexus

What are encapsulated tactile receptors

Wrapped in modified myelin sheath

Ex: tactile corpuscles, lamellated corpuscles, bulbous corpuscles

What determines skin color

Influenced by melanin, carotene, hemoglobin but depends heavily on amount of melanin produced

What are sebaceous glands

They secrete oily sebum which softens and lubricates hair and skin

What is nevus

Overgrowth of melanocytes (moles)

What is basal cell carcinoma

cancerous growth in startum basale

What is squamous cell carcinoma

Cancer in stratum spinosum