Exam 2 Study guide

Question 1

know the types of neuroendocrine signaling and how water soluble and water insoluble hormones are transported

Answer 1

Type of neuroendocrine signaling:
Local Signaling:
-local regulator diffuses through interstitial fluid
Paracrine
Autocrine
Neurotransmission- neurotransmitter diffuses across synapse
Long-distance signaling: must be into blood.
1. Endocrine-
2. Neurosecretory-
Water soluble hormones- circulate freely in blood; bind to cell-membrane RECEPTOR and activate secondary signaling molecules
water insoluble hormones -requires a carrier when entering blood: diffuses across the cell membrane (easily) and binds to and activates intracellular receptor (translocates to nucleus) -affects gene transcription

Question 2

Know the factors that influence hormone concentration

Answer 2

Factors that determine plasma concentration of particular hormone:
-quantity synthesized in host gland
-rate of either catabolism or secretion into blood
-Quantity of transport proteins present
plasma volume changes

Question 3

Know the difference between hormonal, humoral, and neural endocrine gland stimulation

Answer 3

Hormonal stimulation: Hormones influence secretion of other hormones
Humoral stimulation: Changing levels of ions and nutrients in blood, bile, and other body fluids stimulate hormone release
Neural stimulation- neural activity affects hormone release

Question 4

Know which hormones are produced and stored in the anterior and posterior pituitary , respectively

Answer 4

Anterior pituitary hormones : FSH, LH, ACTH, TSH, Prolactin, Growth hormone 
Posterior pituitary (stores and releases hormones)  ADH (vasopressin), Oxytocin

Question 5

Know what regulates secretion of growth hormone, ACTH, TSH, and PTH

Answer 5

Corticotropic-releasing hormone (CRH); stress-related stimuli (low blood glucose, or physical trauma); interleukin-1 (macrophage) regulate secretion of ACTH
TRH (thyrotropin releasing hormone) regulates secretion of TSH.
Growth hormone releasing hormone (GHRH) regulates secretion of growth hormone
-negative feedback loop of calcium levels in blood to parathyroid glands regulates secretion of Parathyroid hormone (PTH) . Low calcium levels stimulate release of PTH. High levels of calcium prevent parathyroid glands form releasing PTH

Question 6

Know the target cells and effects of growth hormone, ACTH, TSH, and PTH expression

Answer 6

GH- growth hormone affects many organs; promotes cell division, cellular proliferation throughout body, slows carb break down, promote synthesis/secretion of insulin-like growth factors which accelerate protein synthesis, enhance lipolysis, TAG breakdown (relate Fatty acids), fat utilization, decrease use of glucose for ATP production in body cells, and promote growth of bone and cartilage
ACTH- has effect on Adrenal cortex, control production and secretion of cortisol and other glucocoritocoids, play a role as part of hypothalamic-pituitary-adrenal axis; enhance FA mobilization form adipose tissue, increase gluconeogenesis, stimulate protein catabolism,
TSH- target cell- thyroid; TSH controls hormone secretion by thyroid gland, maintains growth and development of thyroid, increases thyroid cell metabolism.
-stimulate synthesis and secretion of T3 (triiodothyronine) and T4 (thyroxine)
PTH- target cells are kidney and bone
-stimulates calcium release from bone (increase osteoclasts, and bone resorption)
-stimulate calcium uptake in kidneys, promote formation of calcitriol (active form of Vitamin D) , decrease phosphate blood levels (HPO4-), increase Calcium and Magnesium blood levels.

Question 7

Know the role of calcitonin and PTH in calcium homeostasis

Answer 7

Calcium homeostasis uses Calcitonin when blood calcium levels are very high
and PTH is used when blood calcium levels are low.
-When blood calcium levels fall, parathyroid gland releases PTH to stimulate calcium release form bone and stimulate calcium uptake in kidneys, and increase calcium uptake intestines, helping blood calcium levels rise
-when blood calcium levels RISE- thyroid gland (C cells; parafollicular cells) releases calcitonin which stimulates calcium deposition in bones and reduces calcium uptake in kidneys, allowing blood calcium levels to decline.

Question 8

Know the effects of ADH secretion

Answer 8

posterior pituitary stores ADH (anti-diuretic hormone, or vasopressin).
ADH influences water excretion by kidneys,
produces by supraoptic nucleus
physical activity provides stimulus for ADH to conserve body fluids.
Effects of ADH:
-decrease urine production
-casue kidneys to return more water to blood
-induces sweating and constriction of arterioles (increases blood pressure)
-induced by blood osmotic pressure and blood pressure

Question 9

Know which hormones are produced in the adrenal glands, what stimulates their secretion and where they are produced

Answer 9

Adrenal glands have adrenal medulla and cortex
adrenal medulla (central) produces catecholamines (epinephrine and NE)
stress, exercise that input hypothalamus stimulate secretion of E/NE.
chromafinn cells make E/NE
Adrenal cortex (outer) produces mineralocorticoids (Aldosterone), glucocorticoids(cortisol) and androgens
ACTH sitmulates secretion of androgens
ACTH stimulates secretion of glucocorticoids
renin-Ang-aldosterone stimulates secretion of mineralocorticoids (aldosterone)

Question 10

Know which cells in the pancreas excrete glucagon and insulin

Answer 10

The alpha cells (20%) of islets of langhernas in pancreas secrete glucagon
The beta cells (75%) of islets, in pancreas secrete insulin

Question 11

Understand the role of glucagon and insulin in glucose metabolism

Answer 11

when blood glucose levels FALL, alpha cells of pancreas secret GLUCAGON into blood , allowing liver to break down glycogen into glucose and releases glucose into blood, causing blood glucose levels to rise.
When blood glucose levels RISE, beta cells of pancreas secrete INSULIN and release it into blood. Liver takes up glucose and stores it as glycogen and body cells take up more glucose, causing blood glucose levels to decline.
eventually low glucose levels inhibit release of insulin

Question 12

Understand the structure and composition of muscle tissue

Answer 12

Muscle tissue structure:
-epimysium surrounds entire muscle and then blends into intramuscular tissue sheaths to form tendons
-perimysium surrounds bundle of fibers called fasciculus
-endomysium wraps each muscle fiber and separates it form neighboring fibers
sarcolemma- surronds each muscle fiber and enclose the fiber’s cellular contents
-Sarcoplasm contains the nuclei that contains genes, mitochondria, and other specialized organelles
sarcoplasmic reticulum-provides structural integrity to cell
muscle composition: 75% water, 20% proteins (myosin, actin, tropomyosin are the most abundant proteins) 5% salt and other substances
-single multinucleate muscle fiber contains myofibrils (parallel to fiber’s long axis) and myofibril contain myofilaments (lie parallel to long axis of myofibril) . myofilaments consist of actin and myosin that acccount for 85% of myofibrillar complex.

Question 13

Understand how hormones are regulated during and after exercise- particularly the example we covered in class

Answer 13

Glucagon levels have only slight increase after exercise (especially with untrained individuals, since trained individuals reach steady level of GH)
NE/E levels are low at rest and at elevate after exercise, still at same abolsute exercise intensity
-insulin- increased sensitivity to insulin, decrease insinuslinduring exercise; greatly reduced with training (allow glucose uptake, and supply energy to muscles)

Question 14

Know how muscle alignment affects the muscle fiber

Answer 14

Differences in sarcomere alignment and length strongly affect muscles force and power-generating capacity.
pennate muscles differ from fusiform fibers in three ways: They are generally shorter, possess more individual fibers and exhibit less range of motion
Fusiform (spindle shaped) fibers run parallel to muscles long axis (fiber length= muscle length), and taper at tedious attachment and facilities RAPID muscle shortening
-also complex fusiform arrangement (muscle fibers that terminate in muscle’s mid belly and taper to intact with connectivity tissue matrix allows parallel packing of short fibers within long muscles; create lateral tension at various points along fiber’s surface
Pennate fibers lie at an oblique pennation angle and allows large number of fibers into smaller cross-sectional area. Degree of pennation directly impacts sarcomere number of fibers per cross-sectional muscle. it allows individual muscle fibers to remain short, while overall muscle may attain a considerable length
pennate muscle generate considerable POWER.

Question 15

Know the sequence of events in muscle action

Answer 15

Step 1: generation of action potential in motor neuron causes the terminal axon to release Acetylcholine, which diffuses across synaptic cleft and attaches to specialized ACh receptors on sarcolemma

2. the muscle action potential depolarizes the transverse tubules at sarcomere’s A-I junction.
3. Depolarization of T-tubule system causes calcium release from the lateral sacs of sarcoplasmic reticulum
4. Calcium binds to troponin-tropomyosin in the actin filaments, releasing the Inhibition that prevented actin from combing with myosin
5. Actin combines with myosin-ATP, as well as activates myosin ATPase, which then splits ATP.
   - the reaction’s energy produces myosin crossbridge movement and creates tension.
6. ATP binds to myosin crossbridge; this breaks the actin-myosin bond and allows the crossbridge to dissociate from actin
   - the thick and thin filaments then slide past each other and the muscle shortens
7. Crossbridge activation continues when calcium concentration remains high enough to inhibit troponin-tropoymysoin system
8. When muscle stimulation ceases, intracellular Calcium concentration rapidly decreases as Calcium moves back into lateral sacs of the sarcoplasmic reticulum through active transport that requires ATP hydrolysis.
9. Calcium removal restores inhibitory action of troponin-tropomyosin.
   - in the presence of ATP, actin and myosin remain in dissociated, relaxed state.

Question 16

know the differences between fast-twitch and slow-twitch fibers

Answer 16

Fast twitch and slow-twitch fibers differ in primary mechanism they use to produce ATP, type of motor neuron innervation and type of myosin heavy chain expressed
Fast-twitch fibers:
-High capability for electrochemical transmission of action potentials
-high myosin ATPase activity
-rapid Calcium release and uptake by an efficient sarcoplasmic reticulum
-High rate of crossbridge turnover
- rapid energy generation, quick, powerful muscle actions
-Great speed of shortening and tension development, well-developed short-term glycolytic system for energy transfer, predominate in anaerobic type sprint or energy metabolism. important for stop and go sports (basketball, soccer, lacrosse, field hockey)
Slow-twitch fibers:
-Low myosin ATPase activity
-Slow calcium handling ability and shortening speed
-less, well developed glycolytic capacity the fast-twitch fibers
-Large and numerous mitochondria
-highly fatigue resistant and suited for prolonged aerobic exercise, slow shortening speed, rely on oxidative metabolism

Question 17

Understand the motor unit

Answer 17

motor unit consists of anterior motor neuron the specific muscle fibers it innervates.
The individual and combined actions of motor units produce specific muscle actions
-each muscle fiber generally receives inout from only one neuron, yet a motor neuron may innervate many muscle fibers.
motor unit contains only one specific muscle fiber type (type I or type II) or subdivision of type II with same metabolic profile

Question 18

Know the functional characteristics of a motor unit (twitch characteristics, tension characteristics, and fatiguability)

Answer 18

Motor units three physiologic and mechanical properties of muscle fibers they innervate:
1. Twitch characteristics
-fast twitch, high force and fast fatigue (Type IIb)
-fast twitch, Moderate force, and fatigue resistant (type IIa)
-Slow twitch, Low force, Fatigue resistant (type 1)
-with prolonged aerobic training, fast-twitch muscle fibers become almost as fatigue resistant as SLOW- Twitch fibers.
2. Tension characteristics: ALL or None principle; a stimulus strong enough to trigger Action potential in motor neuron activates all of the muscle fibers in Motor unit to contract synchronously
a motor unit does not Exert force of gradation; either the impulse elicits an action or does NOT. After neuron fires and the impulse reaches NMJ, all fibers of Motor unit react simultaneously.
3. Fatigability - describe the decline in muscle tension nor force and power capacity that occurs with repeated stimulation or muscle activity
-As muscle function changes during prolonged exercise, additional motor unit maintains force output necessary to maintain constat level of performance.

Question 19

Understand gradation of force

Answer 19

Gradation of force- the force of muscle action varies from slight to maximal via 2 mechanisms;

• increased number of motor units recruited (muscle generates considerable force when activated by all of its motor units)
• Increased frequency of Motor unit discharge (repetitive stimuli that reach a muscle before it relaxes increases total tension)

Question 20

Understand proprioreceptors

Answer 20

Proprioreceptors- sensory receptors in the muscles and tendons that are sensitive to stretch, tension and pressure
-they almost instantaneously relay information about muscular dynamics and limb movement to conscious and subconscious portions of Central Nervous system
proprioreceptors- allow continual monitoring of the progress of any sequence of movements and serves modify subsequent motor behavior.

Question 21

Understand neuromuscular fatigue

Answer 21

Neuromuscular fatigue- the decline in muscle tension or force capacity with repeated stimulation or during a given time period.
as muscle function changes during prolonged exercise, additional motor recruitment maintains force output necessary to maintain constant level of performance

Question 22

Understand EPSP and IPSP

Answer 22

EPSP (excitatory postsynaptic potential) - describes the depolarized post-synaptic membrane potential that occurs when positively charged ions( like Na+) flow into post-synaptic cell.
EPSP depolarizes the post-synaptic membrane and make it easier for neuron to fire an action potential
ESPP generated when stimulus triggers opening of sodium channels (allow Na+ in)
IPSP (inhibitory postsynaptic potential)- occurs when some presynaptic terminals produce inhibitory impulses that increase the postsynaptic membrane’s permeability to potassium and chloride ion efflux, thus increasing the cell’s resting membrane potential.
IPSP hyperpolarizes the neuron, making it more difficult to fire
neural inihibition- has protective functions and reduces input of unwanted stimuli (to provide smooth purposeful response)

Question 23

Know the sequence of events in muscle growth

Answer 23

sequence of events in muscle growth:
1. Muscle injury leads to satellite cell activation and proliferation
2. Chemotaxis, or satellite cells migrate to injured fiber
3. Fusion of damaged myofiber with satellite cells(hypertrophy) occur or alignment and fusion not produce new myofibers (hyperplasia)
4. this leads to regenerated myofiber with central nucleus
when you don’t use your muscle or have decrease in muscle mass, smaller muscle fiber, you will have ATROPHY (decreased myonuclear proteins and myofiber CSA)
Hypertrophy- When muscles get bigger, increase myofibrillar proteins and myofiber CSA, increase cross sectional area

Question 24

Know trigger points (causes and treatments)

Answer 24

Trigger points- knots that are present in muscle fiber
Causes:
-poor posture due to sedentary lifestyle,
-injuries from repetitive motions or heavy lifting
- direct injuries such as blunt force trauma, muscle tears, strain or breaking, -overwhelming amounts of mental or emotional stress
Treatments:
-Electrostimulation
-Therapeutic stretching techniques
-Physical therapy
Therapeutic massage
-Pulsed Ultrasound
-Low-Level laser therapy
-corticosteroid injections

Question 25

Know the cause of myofacial pain syndrome

Answer 25

Myofacial pain syndrome: chronic misuse of muscles (postural stress; sitting in incorrect positions or lifting improperly overtime)
occurs due to pressure on sensitive points in the muscle (trigger points) that causes pain in the muscle and sometimes causes pain in seemingly unrelated parts of the body(referred pain)
this syndrome can be caused by repeated injury or muscle overuse.
-chronic pain disorder

Question 26

Know the causes of tendonitis and plantar fasciitis

Answer 26

Tendonitis -inflammation and irritation of the tendon
ex: lateral epicondylitis (tennis elbow)- where micro cracks are seen in tendon caused by tensile forces of muscles. damage to the tendon that bend the wrist back and away from the palm.
caused by overuse (repetitive stress) of tendon during physical activity, leading to tendon to be inflamed, (swollen) and painful
seen in elbow, ankles, knees.
plantar fasciitis- inflammation of the fascia
caused by repetitive motion or putting constant pressure on arch of foot (constant running, jogging) Occurs when the band of tissue that supports the arch of your foot becomes inflamed.