Chapter 10 and 11.5-6: Muscular System and Tissue Flashcards
1
Q
What is the structural organization and primary purpose of muscles in the human body?
A
- There are 600 human skeletal muscles
- Half our body weight
- 3 kinds of muscle tissue: skeletal, cardiac, and smooth
- Major purpose: to convert the chemical energy ATP into the mechanical energy of motion
2
Q
What is the study of the muscular system?
A
Myology
3
Q
What are the functions of the muscular system?
A
- Movement
- body parts, body contents in breathing, circulation, digestion
- Stability
- maintain posture
- prevent unwanted movements
- muscles only PULL
- Control of openings of passageways
- sphincters: internal muscular rings that control the movement of food, blood, and other materials in the body
- Heat production
- by skeletal muscles
- as much as 85% of our body heat
- Glycemic control
- muscles absorb and store glucose as glycogen which regulates blood sugar concentration within normal range
- problems with this contribute to diabetes (athrophied muscle)
4
Q
What are fasicles and connective tissues of muscles?
A
- Fasicles: bundles of muscle fibers wrapped together
- Endomysium:
- thin sleeve of loose connective tissue around each fiber
- electrically insulates each muscle fiber
- Perimysium
- thicker layer of connective tissue that wraps fasicles
- Epimysium
- fibrous sheath surrounding entire muscle
- outer surface grades into fascia
- inner surface projections for perimysium
- Fascia
- sheet of connective tissue that separates neighboring muscles or muscle groups from each other and the subcutaneous tissue
- Can continue into tendon
5
Q
What are circular muscles (sphincters) and two main examples?
A
- muscles that form rings around body openings
- obicularis oris and obicularis oculi
6
Q
What are indirect and direct muscles attachments and their general features?
A
- Indirect attachment
- tendons connect muscle to bone
- collagen fibers of the endo, peri, and epimysium continue into tendon and from there become periosteum and matrix of bone
- aponeurosis: tendon is broad, flat sheet
- retinaculum: connective tissue band that tendons from separate muscle pass under
- tendons connect muscle to bone
- Direct (fleshy) attachment
- little separation between muscle and bone
- muscle SEEMS to emerge directly from bone
7
Q
What is muscle innervation and its subtypes?
A
- Muscle innervation refers to the identity of the nerve that stimulates it
- every single skeletal muscular cell must get a signal from a neuron
- Spinal Nerves
- emerge from intervertebral foramina
- innervate muscles below the neck
- Plexus: weblike network of spinal nerves adjacent to the vertebral column
- Cranial nerves
- arise from the base of the brain
- emerge through the skull foramina
- innervate the muscles of the head and neck
- number CN I to CN XII
8
Q
What is the prime mover of inhalation ? What is the scientific term for inhalation / exhalation?
A
- The diaphragm is the primary muscle for inhalation
- Inhalation = inspiration
- Exhalation = expiration
9
Q
What is the deep muscle of the back?
A
- Erector spinae
10
Q
What are muscle compartments?
A
- a group of functionally related muscles enclosed by fascia
- also contain nerves and blood vessels that supply the muscle group
- intermuscular septa: very thick fascia that separate one compartment from another
11
Q
What is compartment syndrome?
A
- a blood vessel in a compartment is damaged
- blood and tissue accumulate in the compartment
- myoglobin shows up in urine
- pressure increases causing poor blood flow (ischemia)
- nerves begin to die (2-4 hr)
- then muscles begin to die (6 hr)
- treatment: immobilization of limb and fasciotomy (incision to relieve compartment pressure)
- nerves can regenerate but muscle damage is permanent
12
Q
What are three terms for a muscle cell?
A
- muscle cell
- muscle fiber
- myofiber
13
Q
Define the following: myogram, threshold, and twitch
A
- Myogram: a chart of the timing and strength of a muscle’s contraction
- Threshold: minimum voltage necessary to generate an action potential in the muscle fiber and produce a contraction
- Twitch: a quick cycle of contraction and relaxation when stimulus is at threshold or higher
14
Q
Describe the 3 phases of a muscle twitch.
A
- Latent period
- very brief delay between stimulus and contraction
- Contraction phase
- time when muscle generates external tension
- Relaxation phase
- time when tension declines to baseline
- Entire twitch duration varies betweem 7 and 100 ms
15
Q
Define the following:isometric muscle contraction and isotonic muscle contraction
A
- Isometric muscle contraction
- muscle produces internal tension but no movement
- Important in postural muscle function and antagonistic muscle joint stabilization
- Isotonic muscle contraction
- muscle changes in length with no change in tension
- concentric contraction: muscle shortens as it maintains tension (e.g. lifting weight(
- eccentric contraction: muscle lengthens as it maintains tension (e.g. slowly lowering weight)
- muscle changes in length with no change in tension
16
Q
WHat are the 2 main ATP sources?
A
- Anaerobic respiration (fermentation)
- produces ATP in absence of oxygen
- yields little ATP
- generates lactic acid
- possibly contributes to muscle fatigue
- Aerobic respiration
- produces far more ATP
- does not generate lactic acid
- requires a continual supply of oxygen
17
Q
What occurs in the following processes: immediate energy retrieval, short term energy retrieval, and long term energy retrieval?
A
- Immediate energy
- short, intense exercise (6 seconds of sprinting)
- oxygen is briefly provided by myoglobin but quickly depleted
- phosphate transfers: borrows phosphate groups from other molecules and transfers them to ADP
- Myokinase: takes P from ADP
- Creatinekinase: obtains P from creatin phosphate
- Short term energy (30-40 seconds)
- occurs in cytoplasm
- glycolysis: glucose broken down unto pyruvic acid which is converted into lactic acid
- 2 ATP produced per glucose
- no oxygen
- Long term energy
- occurs in mitochondria
- pyruvic acid broken down into CO2 and water
- Must have oxygen present (used to form water)
- 32-38 ATP generated (40% of energy)
- rest is released as heat (60% of energy)
