Locomotion + Endocrine I

Locomotion

Locomotion

 the act of moving from one place to another

Smooth

muscle in the walls of hollow internal organs (ex: stomach, intestines) & walls of passageways (ex: arteries & veins)

Striated

cardiac, skeletal muscle

smooth

cardiac

2 types of involuntary muscle

skeletal

voluntary muscle

sarcomere

• Smallest functional unit of muscle

• contractile unit within the muscle fiber

• Area between 2 Z lines

actin

working

ATP

cocking

Cross-bridge cycle

1. Mysoin cross bridge attaches to the ______ myofilament

2. ________ stroke – the myosin head pivots and bends as it pulls on the actin filament, sliding it toward the M line

3. As new ___ attaches to the myosin head, the cross bridge detaches

4. As ATP is split into ADP and P_i, _______ of the myosin head occurs

actin

Tropomyosin

Troponin

• Thin filaments in cross-bridge cycle

  • ______: contains a myosin-binding site

  • _____________: arranged end to end along actin, partially cover the binding site

  • ________________: holds tropomyosin in this position, prevents myosin from making contact with actin, contains a Ca2+ binding site

Myosin

heads

binding

• Thick filaments in cross-bridge cycle

  • ______________ (thick) is a contractile filament (protein)

  • Containing 2 globular _________ and a long tail

  • Each globular head of the heavy chain of amino acids contains 2 ____________ sites, one for actin and the other for ATP

sodium

calcium

muscle

contraction

relax

series of events associated with the contraction of a muscle

• Open channels allow an influx of _________ ions into the cytoplasm of the muscle fiber

• The sodium influx sends a message within the muscle fiber to trigger the release of stored _________ ions

• Calcium ions diffuse into the _________ fiber

• Relationship between the chains of proteins with the muscle cells change leading to the _________

• Muscle fibers _________ when the nervous system signal is no longer present

motor neurons

• Control muscle contraction

• Each branch innervates a single muscle fiber

Motor unit

a motor neuron and all of the fibers it innervates

Neutral buoyancy

animal has the same buoyancy as water

SA:V

heavy

light

• Animals can achieve neutral buoyancy by

  • Increasing __________ ratio

  • Removing __________ material

    • Ex: loss of calcium carbonate or phosphate in skeleton

  • Adding very __________ material

    • Increasing amounts of light fats and oils

    • Increasing the amount of gas in the body

Gas gland

gland that fills the separated swimbladder in more “advanced” fish with gas from the blood supply

diffusion

basic mechanism involved in gas gland functioning

capillary

high

abundant

low

Red muscle fibers: well-developed ____________ supply, high/low concentration of myoglobin, ____________ mitochondria, high/low speed

sparse

low

short

White muscle fibers: _______ capillary supply, high/low volume density of mitochondria, short/long bursts

Pectoralis

supracoracoideus

Why do most birds present a relation 1:3 in the Pectoralis : Supracoracoideus muscles?

• ____________ powers downstroke and __________________ powers upstroke (less energy demanding)

gliding

• requires less anatomical & physiological specialization than true flight

  • Any structure that increases SA can improve the ability to do this

Soaring

• only in birds, dramatically reduces the costs of flight

  • Efficiency is enhanced by strategies that capitalize on natural air movements

Electromagnetic induction

•  induced electrical fields detected by highly sensitive electroreceptors 

  • Ex: ampullae of Lorenzini in elasmobranchs

Radical-pair-based magnetoreception

• magnetic compass of birds is an inclination compass, which detects the angle between magnetic field lines and gravity

  • Orientation depends on light

  • Eyes and/or pineal organ may be involved

  • Cryptochrome proteins in the eye are the only photoreceptor molecules known in vertebrates that are affected by light and are magnetically sensitive

    • → birds could perceive input as a visual cue

electromagnetic

magnetic

radical

three possible mechanisms to perceive Earth’s magnetic field

• _______________________ induction

• __________-particle based magnetoreception

• ___________-pair-based magnetoreception

fat

increases

protein

Long distance migrants show different changes in preparation for migration

• ____ deposition rate – behavior (hyperphagia & territoriality) – increases

• Increases/decreases in the size and activity of gut and liver, digestion times, and digestive enzymes

• Increase _________ carriers

neuron

nonneural

Neurosecretory

paracrine

Describe the four ways in that chemical signals act over short and long distances within the body 

• _________ releases neurotransmitter molecules that act on receptor molecules of the postsynaptic cell

• _________ endocrine cell secretes hormone molecules that enter a capillary and are carried throughout the bloodstream

• _________ cell secretes hormones like a neuron releases neurotransmitter, and the hormone enters and leaves the blood in the same manner as a hormone from a nonneural endocrine cell

• _________ and autocrine signals diffuse locally to activate receptors on neighboring cells (paracrine) or on the same cell (autocrine)

sensory

motor

CNS

basic functions of the nervous system

• Processing of inputs (sensory info from receptors) → _________ neurons

• Organization of motor activity (control of the effectors, primarily muscles) → _________ neurons

• Process of decision-making (intervening between the other 2 processes) → ___

Resting potential (RP)

• resulting electrochemical equilibrium

  • Inside of cell is negatively charged relative to the outside

  • All cells have this, but neurons use these fundamental cellular properties in much more elaborate forms of info processing

Active potential (AP)

• rapid change, all or nothing; rapid and very transient reversal of the membrane potential (from the negative resting state to slightly positive), which sweeps along a neuron

  • Absent in any other cell type in animals

  • → very rapid depolarization followed by a slightly slower repolarization (often with an undershoot to a potential value a little below the normal RP)

  • Key performer = voltage-gated Na+ channel

  • Secondary role played by voltage-gated K+ channel

Chemical synapse

zone where 2 neuronal surfaces lie close together and a chemical transmitter (neurotransmitter) diffuses across the gap between them (synaptic cleft)

CNS

brain (within cranium) + dorsal spinal cord

Peripheral nervous system

cranial nerves, spinal nerves, autonomic nervous system, somatic (or voluntary nervous system)

Autonomic nervous system

sympathic + parasympathetic nervous system

Sympathetic nervous system

rapid response to stressful situations

Parasympathetic nervous system

• control of activities that occur at rest

  • Ex: digestion, sexual arousal, etc.

rapid

The speed of response of the nervous system is

slow

The speed of response of the endocrine system is

neurons

hormones

1. Present an example of the interaction between the nervous and endocrine system. 

   • __________ secrete hormones

   • Secretion of _____________ by some cells controlled by the nervous system

Lipophilic

highly lipid soluble

Hydrophilic

highly water soluble

neurotransmitters

Type of chemical messenger in nervous system which are released into the synaptic cleft

hormones

Type of chemical messenger in the endocrine system which are released into the blood

wired

The nervous system is a ________ system while the endocrine is not.

• Steroid (lipid-soluble)

• Peptide (water-soluble)

• Amine

What are the three groups of hormones if we classify them according to their chemical group? 

• Cholesterol 

• Secreted in: gonads, placenta, adrenal cortex

Steroid hormones are synthesized from__________ and are secreted in ___________ (3)

Mineralocorticoids

Glucocorticoids

Reproductive hormones

What are the three major classes of steroid hormones in vertebrates? 

Mineralocorticoids

steroids involved in regulating sodium uptake by the kidney and are important for fluid and electrolyte balance in the body

Glucocorticoids

(cortisol, cortisone, corticosterone): stress hormones, have widespread actions including increasing glucose production, increasing the breakdown of proteins into amino acids, increasing the release of fatty acids from adipose tissue, and regulating the immune system and inflammatory responses

Reproductive hormones

(estrogens, progesterone, testosterone): regulate sex-specific characteristics and reproduction

stored

Lipid-soluble hormones can’t be __________, so they must be synthesized on demand

Carrier proteins

long distance transport

specific

• Some steroids may have __________ carrier proteins (binding globulins)

• Some steriods bind nonspecifically to generalized carrier proteins

  • Ex: albumin – principal carrier protein in vertebrate blood

transmembrane

cytoplasmic

expression

lag

1. Describe the mechanism of action of lipid-soluble hormones

   • Steroids can bind to _______________ receptors or to receptors inside the cell

   • When steroid messenger binds to a transmembrane receptor, it activates a _____________ signal transduction pathway, which causes rapid non-genomic effects that do not require changes in transcription or translation

   • Intracellular (nuclear) steroid receptors act as transcription factors, controlling the ___________ of target genes

   • → ___ time between the binding of the messenger and observation of the initial effects

water

vesicles

exocytosis

fast

binds

rapid

1. Describe storage and mechanism of action in peptide hormones. 

   • ________-soluble

   • Packaged into ________ for either immediate release or storage for later use

   • Signaling cell releases the active peptide hormone by ________

   • Fast/slow acting– necessary for the regulation of fast change in physiological processes

   • Pep horm ________ to ligand-binding domain of a transmembrane receptor → receptor changes shape, communicating the signal carried by the ligand across the cell membrane, without the ligand itself needing to cross the lipid-rich membrane

   • Transmembrane receptors activate cytoplasmic signal transduction pathways that cause ________ changes in the activity of the target cell

Ligand

general term for any small molecule that binds specifically to a protein

Tryptophan-derived (water soluble)

amine hormone classification in which melatonin is secreted from the pineal gland

Tyrosine-derived

amine hormone classification

• Catecholamines (water soluble): 

  • Epinephrine (adrenaline) and Norepinephrine, secreted from the adrenal medulla

  • Dopamine: neurotransmitter secreted by the hypothalamus

Iodothyronines (lipid soluble)

amine hormone classification with  thyroid hormones synthesized by the thyroid gland

increase

1. What does it mean that a receptor has become saturated with ligand? 

   • Adding more ligand will not __________ the response in the target cell

Signal transduction cascade

activated substance A activated substance B, which activates C, so on until the end of the cascade, thus greatly amplifying the original signal caused by binding of a molecule of chemical messenger

amplification

Longer signal transduction cascade → greater degree of signal _____________

tissues

cells

inactivation

1. Name two possible ways to terminate ligand-receptor signaling

   • Ligand removed by distant ____________

   • Ligand taken up by adjacent __________

   • Receptor __________

Negative feedback loop

•  hormone causes changes in its control pathway that tend to suppress its own secretion

  • Variable is back to a predetermined set point

  • Serves to stabilize blood concentrations of hormones

Positive feedback loop

•  system responds to a change in the regulated variable by causing further deviation from the set point

  • Less common

• Synergisms

• Permissiveness

• Antagonism

• Neural modulation

1. How can hormones interact with each other? 

   • ____________: one hormone amplifies the effect of another 

   • ____________: the presence of one hormone is required for the other to exert an effect

   • ______________: one hormone opposes the action of another

   • ____________ ____________: neurons can increase or decrease hormone secretion

action

exocytosis

1. What is the relation between hypothalamus and pituitary in the posterior lobe of the pituitary? 

   • When the neurosecretory cells are stimulated, they generate ___________ potentials that propagate from the hypothalamus to their axon terminals in the posterior pituitary

   • Here they release hormone by ____________ into the extracellular fluid near capillaries and the hormone diffuses into the blood

Antidiuretic hormone (ADH) also called vasopressin

hormone that acts in the nephron – changes the permeability to water in the distal convoluted tubule and collecting duct

impermeable

No ADH: distal tubules are ___________ to water, then water can’t be reabsorbed, so dilute urine is formed

concentrated

ADH present: collecting ducts are water permeable, water is withdrawn, _____________ urine is formed

low

1. What is the role of Renin-angiostensin- aldosterone system in water balance? 

   • Corrects high/low extracellular fluid volume

water

sodium

1. What is the main difference between ADH and aldosterone? 

   • ADH makes the tubules more permeable to _______

   • Aldosterone makes the tubules more permeable to _______ ions, increasing the water absorption by creating an osmotic pressure