biomed Flashcards
Postural Control?
balance=controlling body’s position in space for stability and orientation
Postural stability/equilibrium
balance=ability to control COM over BOS
postural orientation
= POSTURE = maintaining an appropriate relationship between different segments of the body and between the body and the environment
Center of Mass
= centralized point of the body’s mass
Base of support
= area created by where the body comes in contact with the support surface which supports its mass
Center of pressure
= center of the distribution of the total force applied to the supporting surface
ankle strategy
Distal to proximal muscle activation
Body sways at ankles with hips and knees extended
Utilized as response to small perturbations on firm surfaces
EXAMPLE:
If platform moves back, the body will move forward, so then need posterior muscles to activate in order to pull the body back
If the platform moves forward, the body will move back, so then need anterior muscles to activate in order to pull the body forward
hip strategy
Proximal muscles activated first
Produces large, rapid motion at the hip joint
Utilized when standing on narrow BOS, on soft surface, or during larger, faster perturbations
Step strategy
Happens when the other systems aren’t fully working and with large perturbations or with very slow response of the system
Role of brainstem and cerebellum in controlling balance?
Important for integrating sensory inputs
M/L vestibulospinal tracts and reticulospinal tracts may carry signals for Automatic Postural Responses
Role of basal ganglia in controlling balance?
Adaptation to sudden changes in task
What is the role of 3 areas in the cerebral cortex in controlling balance?
Supplementary motor area: anticipatory strategies
Temporo-parietal cortex: sensory integration, body verticality
Sensorimotor cortex: receives somatosensory input
Where are volitional actions located in the cortex?
Are likely represented in the primary motor cortex.
Each muscle has multiple representations within the motor cortex. → Fits the context of synergies
There is considerable overlap between multiple muscles transversing different joints.
Which synergy gets activated in M1 depends on another planning and association areas in the cerebral cortex, the cerebellum, and basal ganglia.
Location of reactive movements in CNS?
Spinal and brainstem networks with some cortical inputs.
What is Arthrogenic Muscle inhibition or Arthrogenic Muscle Response (AMR)?
Continuing reflex reaction of the musculature surrounding a joint after distension or damage to the structures of that joint
What is the pathophysiology of AMR?
loss of feedback from mechanoreceptors is believed to be the underlying mechanism of weakness.
Damaged mechanoreceptors may cause a gamma-loop dysfunction at the level of the spinal cord where 1a afferent fiber (sensory fibers that respond to muscle length and velocity) feedback is altered and limits alpha-motor neuron depolarization. There are other spinal reflex pathways thought to be at play, such as flexion reflex, H-reflex and group I nonreciprocal (Ib) inhibitory pathway.
What are the functions of skin?
Protection, temperature regulation, sensation, metabolism, communication and identity
What are the primary anatomical layers of skin?
Epidermis
Dermis
Subcutaneous tissue
Function of the epidermis?
provide surface protection
Function of the dermis?
provide tensile strength, house appendages (glands, hair follicles)
Function of subcutaneous tissue?
cushioning
Two functions of sebaceous glands?
Secrete sebum to lubricate the skin
Create an “acid mantle” to prevent infection
What are the four characteristics of aging skin?
Epidermis, dermis, and subcutaneous tissue layers become thinner.
Dermal-epidermal bond becomes more fragile
Decrease in the quantity of dermal cells, appendages, blood vessels, and nerve endings.
Decreased elastin.
Describe the difference between full and partial thickness tears.
Full thickness: injury through both the epidermis and dermis, involves subcutaneous tissue.
Partial thickness: injury through the epidermis, may involve part of the dermis.
Describe how the methods of healing differ dependent upon tissue loss.
Full thickness: occurs via primary, secondary, or delayed primary intention, scar formation.
Partial thickness: occurs via epithialization, regeneration of epithelium. NO scar formation.
How does scar tissue differ from skin?
Collagen fibers have less tensile strength, skin is less elastic.
No elastic fibers; no elastic recoil
No dermal appendages; no lubrication
What are the phases of wound healing?
Inflammation
Proliferation
Maturation
How long does the inflammatory phase typically last?
0-6 days, maybe be longer
What is the typical clinical presentation of inflammation?
painful, red, hot, swollen
What are the 3 major processes of inflammation?
hemostasis, clean-up, trigger repair
What is the role of neutrophils?
kill microbes
release cytokines
What is the role of macrophages?
remove debris
secrete growth factors and cytokines to initiate the repair phase
What is the role of lymphocytes?
downregulate inflammation
promote granulation
How long does the repair/proliferation phase typically last?
Day 4-14
What is the typical clinical presentation of the repair/proliferation phase?
Granulation tissue (beefy red tissue in wound bed) Epithelial cells around the edges of the wound (pink/silver layer of cells)
What are the 4 major processes of the repair/proliferation phase?
Neovascularization
Granulation
Contraction
Epithelialization
How long does the maturation phase last?
Day 8 to 1 year
What are the 2 major processes of the maturation phase?
collagen maturation and reorganization
reduction in vascularity (pink > white)
What influences how new collagen is organized?
mechanical stresses applied to the tissue
What is the typical clinical presentation of the maturation phase?
Wound closed
Pink scar
What 3 general factors delay wound healing/influence the formation of a chronic wound?
local factors
systemic factors
iatrogenic factors
What are four signs of infection?
induration (hard swelling)
fever (local or systemic)
erythema (redness, irregular borders)
edema
What would be an important ABI value to signify poor perfusion/poor healing potential?
ABI < .4 = poor healing potential
List some systemic factors that can delay wound healing.
stress
nutrition and obesity
temperature
comorbidities
List some iatrogenic factors that can delay wound healing.
medications
topical agents
trauma as a result of inappropriate treatment
Name three potential complications that can occur during healing.
dehiscence
excessive scarring
arthrofibrosis
