Physiology Exam 3 (Muscle, Immune, and Digestive systems)

Reasons for muscle fatigue

-Decrease in ATP -Buildup of lactic acid (decrease in pH) -Lack of calcium (decrease in Ca2+) -Buildup of ADP -Decrease in acetylcholine -Decrease in oxygen -Decrease in glucose/glycogen -Central fatigue- mental drive to complete something ends

Properties of muscles

-electrical excitability -contractility -extensibility -elasticity

Muscle functions

-producing body movements -stabilizing body positions -storing and moving substances within the body -generating heat (thermogenesis)

Innate immunity

Non-specific; ability of body to defend itself against microbes and other foreign substances without the use of specific recognition of invading pathogen.

motor unit

Somatic neuron and muscle fiber it innervates, are recruited in progressive way depending on contractile force needed

Pacemaker potentials

Spontaneous potentials that always reach threshold

Contraction cycle

1. ATP hydrolysis 2. Attachment of myosin to actin (crossbridge formed) 3. Power stroke 4. Detachment of myosin from actin due to ATP attaching to mysoin

3 types of muscle proteins

1. Contractile 2. Regulatory 3. Structural

2 signals needed for clonal selection

1. Recognition of antigen 2. Costimulation

Cytotoxic (CD8) T cells

Attack infected body cells, cancer cells, foreign cells

Structural muscle proteins

Contribute to alignment, stability, extensibility, and elasticity

Excitation in excitation-contraction coupling

Electrical event (Muscle action potential)

Antibody mediated immunity

Involves use of B cells

Cell mediated immunity

Involves use of T cells to eliminate specific antigens

Contractile muscle proteins

Made up of myosin and actin

Regulatory muscle proteins

Made up of troponin (binds Ca2+) and tropomyosin (covers myosin-binding sites on actin)

Contraction in excitation-contraction coupling

Mechanical event (Shortening of sarcomere)

Jejunum and ileum

Where absorption occurs in small intestine

Ascending colon, transverse colon, and descending colon

Where in large intestine these processes are done -Bacterial fermentation occurs -Absorption of water and some vitamins -Make feces

Calmodulin

binds Ca2+ in smooth muscle due to lack of troponin

Amylase

chemical digestion enzyme that breaks down carbs

Lipase

chemical digestion enzyme that breaks down lipids

Proteases

chemical digestion enzyme that breaks down proteins

Oral cavity

chew food into smaller bits and where both chemical and mechanical digestion occur

Slow-wave potentials

constant depolarizations and repolarizations that do not necessarily reach threshold

Organization of skeletal muscle

muscle --> fascicle --> muscle fiber --> myofibril --> myofilaments --> sarcomere

Smooth muscle

not striated and involuntary; found in hollow organs

Small intestine

organ in charge of absorption of nutrients (Takes around 7 hours)

Large intestine

organ in charge of absorption of water and production of feces (Takes around 9 or more hours)

Stomach

organ which liquify and chemically and mechanically digest food (Takes about 4 hours)

Liver and pancreas

organs in charge of releasing secretive enzymes into GI tract

Autonomic nervous system

regulates smooth muscle contraction

Helper (CD4) T cells

secrete cytokines

Cardiac muscle

striated and involuntary; found in the heart

Skeletal muscle

striated and voluntary; found attached to bone

Duodenum

where bile and pancreatic juice mostly finish digestion

Anus

where defecation occurs

Electrical excitability

Ability to respond to certain stimuli by producing action potential

Contractility

Ability of muscle to contract forcefully when adequately stimulated

Elasticity

Ability of muscle to return to original shape after contraction or lengthening

Extensibility

Ability of muscle to stretch without being damaged

Adaptive immunity

Ability to defend yourself against SPECIFIC microbes and other foreign agents