Animal Physiology Test 3

Explain what Endocrine Control is

Endocrine cells release hormones into the bloodstream to mediate the endocrine control. All body cells are potential targets of a hormone, but only those with specific receptors for the hormone to actually respond. Hormonal control is slower, longer lasting and less spatially circumscribed than neural control.

Explain what Neural Control is

Control by nervous system involves neurons that send axons to discrete postsynaptic cells. neurons propagate rapidly conducting action potentials to transmit signals from point to point within the cell. They exert fast, specific control by releasing neurotransmitters at synapses.

What are the main differences between Endocrine and Neural control?

Endocrine:

- Hormones are released into blood

- Slow and broadcast

- prolonged and widespread activities such as metabolic changes

Neural:

- signaling is precisely targeted

- fast and finer control (spatially and temporal)

- primarily controls moment-to-moment movements of individual muscles

Define and Describe Action Potential

The electrical signal of an excitable cell. It is voltage-dependent, all-or-none electrical signals. Results from voltage-dependent changes in membrane permeabilities to ions because ion channels that produce this have openings that depend on membrane potential.

1) Triggered by any depolarization of the membrane that reaches a critical value of depolarization

2) After this, has a rapid rising phase

3) Reaches a peak more positive than zero potential (overshoot)

4) Followed by rapid repolarization (falling phase)

Define Hormone

A chemical substance secreted by endocrine tissues into the blood that acts on a target tissue to produce a specific response

Define Neuron

A cell specially adapted to generate an electrical signal, most often in the form of a brief, self-propagating impulse (or action potential)

Define Synapses

The specialized site of communication between a neuron and its target cell

Define Dendrites

a short branched extension of a nerve cell, along which impulses received from other cells at synapses are transmitted to the cell body.

Define Neurotransmitter

A chemical substance released by a nerve ending at the synapse. It acts on the adjacent neuron to stimulate, inhibit, or change its activity.

Define Axon

A long narrow outgrowth of a neuron by which information is transmitted to other neurons

Define Innervate

To supply/provide nerve fibers to/from organ and tissue

Define and Compare Efferent and Afferent neurons

Efferent neurons:

- relay control signals (instructions) from the Central Nervous System to target cells under nervous control (such as muscle or secretory cells)

- "To carry off"

Afferent neurons:

- relay sensory signals to integrative centers of the Central Nervous System

- "to bring toward"

Describe(or draw) what a neuron structure is and what the function of each part is

Dendrites: branching process where synaptic input occurs

Soma: The cell body of a neuron

Axon: the conduction component of a neuron, serves to propagate action potentials along its length

Myelin Sheath: periodic thickenings that insulate the axon

Axon Terminal: constitute the place where neuronal input occurs

Describe/Trace the neural pathway from stimulus to response

(example used: Cockroach's jump)

It detects air currents or sound waves with its wind-receptor hairs. This stimulus triggers action potentials in sensory neurons in the peripheral nervous system (PNS). These signals travel to the central nervous system (CNS) where they connect with interneurons. The sensory neuron activity prompts interneurons to generate their own action potentials. Interneurons, in turn, connect with motor neurons and excite them. When motor neurons are excited, they stimulate the leg muscles to contract, resulting in a jump response

Define Excitable cell

Cells that can rapidly change membrane potential/generate action potential in response to a chemical or electrical stimuli

Define Voltage-Threshold

It is a critical membrane potential level that must be reached or exceeded for an excitable cell, such as a neuron or a muscle cell, to generate an action potential. In other words, it's the minimum electric potential difference (voltage) that a cell's membrane must reach to trigger the initiation of an action potential.

Define Absolute Refractory Period

The time during and immediately after an action potential in which the voltage threshold is infinite (no depolarization can exceed threshold and no new action potential can be created)

Define Relative Refractory Period

The brief period following an action potential during the generation of another action potential is relatively difficult because voltage conditions are further than usual from the threshold

List the factors that affect conduction velocity of a neuron

1. Axon Diameter, 2. Myelination Sheath, 3. Temperature

Define Biological Clocks

Animals and other organisms that possess endogenous physiological timing mechanisms

Define Temporal Organization

A timed pattern of change in physiology or behavior that is independent from a change in environment

Define Endogenous Rhythms

Rhythms that continue in the absence of environmental information

Define Circadian Rhythm

An endogenous rhythm that has a period of about a day (24 hours)

Define Free-run/ Free-running Rhythm

When environmental cues are absent, and the biological rhythm persists

Define Entrainment

The process by which a biological rhythm is brought into phase with an environmental rhythm

Define Zeitgeber/Phasing factor

An environmental cue that is capable of entraining (setting the phase) of a biological rhythm

- "Time Giver"

Why are biological clocks advantageous to physiology (give examples)

- Enables an animal to prepare and anticipate an environmental change

- Feed-forward control: initiates changes in physiological systems rather than correcting for changing after they happen

- providing temporal order to physiological processes so they occur appropriate time of day

- enables animals to measure changes in photoperiod

- enables some animals to use the sun to determine the compass direction

Define Neurohormone

A hormone secreted by a neuron into the blood

Define Paracrine

A locally acting chemical signal that binds to receptors and exerts a regulatory effect on cells in the neighborhood of the cell that released it

Define Receptor molecule

A protein that binds non-covalently with specific molecules and as a consequence of this binding, initiates a change in membrane permeability or cell metabolism

List and Describe the 3 chemical classes of hormones

1) Steroid:

- synthesized from cholesterol

- Lipid soluble, as in they diffuse through the cell membranes to reach receptor molecules located inside the target cell

2) Peptide:

- Structures from chains of amino acids

- Soluble in aqueous solutions

- Vary in Molecular size

3) Amine:

- modified amino acids

- secreted by the vertebrated pineal gland

How does a hormone class alter the activity of a target cell?

Peptide and Protein Hormones:

- Chains of amino acids

- Change the activities of pre-existing protein molecules

Steroid Hormones:

- Lipid soluble

- made from cholesterol

- edits gene expression

Amine Hormones:

- Modified amino acids

- also affects gene expression

How does a hormone travel though the blood?

Carrier proteins in the blood bind to some hormone molecules reversibly and non-covalently. Bonding with carrier proteins ensures that lipid-soluble hormones remain dissolved in the aqueous plasma. Typically the free and bound forms of hormones are present in the blood at concentrations dictated by mass-action equilibrium

what are the many physiological functions to regulate that the endocrine system integrates

- The mammalian stress response

- nutrient metabolism

- salt & water balance

- calcium metabolism

List the 5 patterns of hormonal control (this one is long, sorry)

1) Endocrine control of a single of any single physiological system likely involves more than one system

2) A hormone that affects the functions of one physiological system probably affects other systems as well

3) Hormones may interact with one another synergistically, permissively, or antagonistically

4) Because responses of a target cell to a hormone depend on the physiology of the target cell different target cells can express different types of responses to a single hormone

5) Many endocrine controls operate in tightly coordinated ways with neural controls

6) Many molecules that function as hormones in one context function as different types of chemical signals in other contexts

List the 6 main groups of chemical signals based on distance of action

1. Gap junctions:

- Are formed by connexon protein channels between adjacent cells

2. Cell adhesion molecules:

- on the external surface of cell membranes play important roles in signaling between adjacent cells involved in embryonic development, wound repair, and cellular growth and differentiation

3. Neurotransmitters:

- are released by presynaptic neurons in response to electrical signals

4. Paracrines and autocrines:

- diffuse relatively short distances to influence cells in the local environment

5. Hormones and Neurohormones:

- are carried by both blood and specialized for long-distance communication within the animal

6. Pheromones and Kairomones

- Some chemical signals act outside the animal. For Pheromones, animals of the same species use it to communicate with each other. Animals detect Kairomones to obtain chemical information about members of a different species

List key processes that much be coordinated, both internally and externally, for reproduction to take place (sorry this is awful)

Internal Processes:

- Gametogenesis: The production of gametes (sperm in males and eggs in females) is a fundamental internal process for reproduction. This involves the maturation and development of specialized reproductive cells.

- Hormonal Regulation: Hormones play a crucial role in regulating reproductive processes. In males, the hormone testosterone is essential for sperm production, while in females, hormones like estrogen and progesterone regulate the menstrual cycle and ovulation.

- Fertilization: The fusion of a sperm cell with an egg is a critical step in reproduction. It requires the successful navigation of sperm through the female reproductive tract to reach the egg.

- Embryonic Development: Once fertilization occurs, a fertilized egg (zygote) undergoes a series of divisions and differentiations to develop into an embryo. This process must be carefully coordinated to ensure proper development.

- Implantation: In viviparous species, such as mammals, the embryo must implant itself in the uterine wall for further development. This process requires the synchronization of the embryo's development and the receptivity of the uterine lining.

External Processes:

- Courtship and Mate Selection: In many species, individuals engage in courtship behaviors to attract and select mates. This involves communication, displays, and rituals to ensure compatible mating pairs.

- Reproductive Timing: The timing of reproduction is often influenced by environmental cues, such as photoperiod or temperature. Many species have specific breeding seasons when conditions are optimal for reproduction.

- Mating: The act of mating itself must be coordinated, often involving the physical alignment of male and female reproductive organs. In some cases, it may require complex behaviors or rituals.

- Nesting and Parental Care: In species where parental care is necessary, the building of nests, incubation of eggs, and the care of offspring require coordination between parents.

- Nurturing Environment: The environment in which the offspring will develop is critical. This includes providing the right nutrients, temperature, and protection from predators or adverse conditions.

- Postnatal Care: In some species, parental care continues af

List the 6 key aspects of reproduction that are studied by physiologists (this is a brief answer of what exactly the book says they study)

1. Control of the annual cycle of reproduction: (the adaptive implications of seasonality and the mechanisms by which reproduction is coordinated with the annual environmental cycle)

2. Mate association: (the signaling and sensory processes that mediate these activities, including pheromones and behaviors such as estrus)

3. Functions of reproductive organs and cells: (how eggs are made, how erections occur, how sperm cells are sustained and sometimes transformed after being discharged from a male, how milk is synthesized, etc.)

4. Coordination of the reproduction organs by neural, endocrine, and neuroendocrine processes: (how an animal's reproductive organs are coordinated and controlled during an episode of reproductive activity)

5. Delivery of resources to offspring by parents: (the implications of provisioning energy and nutrient budgets of parents and offspring, and they study the mechanisms of offspring provisioning)

6. Physiology and environmental relations of the young: (the distinctive functional attributes and adaptations of the young at each stage of development--and the maturation process itself- emphasizing that reproduction is successful only if the young succeed in meeting each challenge they face in their environment, so they survive to attain sexual maturity)

List environmental cues that animals use to time reproduction

- Low Food availability

- Temperature and Photoperiod

- Latitudal trends

- Distinct Habitats

Define semelparous/parity

When each individual is physiologically programmed to reproduce at only a single time in its life

Define iteroparous/parity

When individuals are physiologically capable of two or more separate periods of reproductive activity during their lives

Define prenatal

Providing nutrients before offspring are born/hatched transfer of nutrients to offspring by the bloodstream

Define postnatal

providing food/nutrients to young after they are born or hatched

What are some strategies animals use to provision offspring?

- yolk-rich eggs have food for offspring

- nutrients from bloodstream of mother to bloodstream of offspring

- snail eggs written snail eggs

- great white branch (great white sharks)

- lactation (cows, humans, etc.)

- gather food (wolves bringing food to young)

- lay on live (wasps laying eggs on life organisms)

What are the advantages of External fertilization?

- More offspring can be produced

- More genetic variability = more adaptive offspring

- Less parental cost

What are the disadvantages of External fertilization?

- Easier to fall into predator's grasp

- No choice in suitable/non-suitable mate

- species recognition from sperm to egg

What are the advantages of Internal fertilization?

- Females can choose suitable mate

- Less chance of cross-species mix up

- Offspring essentially protected more

What are the disadvantages of Internal fertilization?

- Parents have to put more energy into it

- Sperm have to gain access to entry in egg

Define Reflex

Involuntary graded behavioral response to specific stimulus

Define Afferent

Going toward. (example: afferent blood vessel carries blood toward an organ of interest)

Define Efferent

Going away. (example: efferent blood vessel carries blood away from an organ of interest)

Define reciprocity

A principle of motor control in which signals that activate motor neurons and muscles also inhibit activation of antagonist motor neurons and muscles

What are the differences in the neural circuitry of vertebrates and invertebrates

Vertebrates:

- more neurons (muscles requires 100's)

- Can't be uniquely Identified, but can be recognized as members in a population

- Many neurons participate in certain functions

Invertebrates:

- Fewer neurons

- Arthropods receives few neurons for muscles

- May be uniquely identified neurons

- Single individual neurons play functional roles in these circuits

Define Rhythmic behavior

A stereotyped, repetitive sequences of movement such as walking, swimming and flying in which the motor output is stable, repeatable and predictable from cycle to cycle of the activity

Define CPG

Central pattern generator which is a neural circuit that generates a behaviorally significant pattern of motor output in space and time without requiring temporally patterned sensory input

Define Oscillator

Something that moves rhythmically around a certain point.

Explain the process of CPG, and how sensory input can affect it

External stimuli can cause entrainment on CPG. CPG you are continually sending signals that go through an oscillator. Don’t consciously think about every step you take. CPG allows us to not send a new signal to our muscles with every step we take, CPG keeps steps going. CPG is a neuron circuit loop that just keeps itself going. It is an intuitive process that keeps signals from primary motor cortex going as long as youwant, a lot of CPG happens within the spinal cord. CPG is continually going with oscillators that working and there can be inhibition.

What are the vertebrate brain areas in the context of controlling and coordinating movement?

- Primary motor cortex: controls movement indirectly

- Premotor areas: control differing categories of complex movement

- Cerebellum: concerned with motor coordination, posture and balance

- Basal Ganglia: initiation of of intended movement and suppression of unwanted movement

Define muscle

A group of muscle cells (muscle fibers) and associated tissues. Has 3 categories: Smooth, Skeletal and Cardiac

Define Myosin

A molecule motor found in many types of cells that converts chemical energy of ATP into mechanical energy of motion. In muscle cells it functions as a contractile protein.

Define Actin

One of the contractile proteins of muscle cells. Globular G-actin monomers polymers to form the filamentous F-actin of the thin myofilaments.

Define Striated muscle cells

Muscle that consists of cells in which the thick myosin and thin actin filaments are arranged in sarcomeres. The sarcomeres in a cell are aligned in register to form stripes or striations at right angles to the long axis of the cell

Define Skeletal muscle

Muscle that produces locomotory movements or other external movements of the body. In vertebrates, this muscle is attached to the exoskeleton. In invertebrates it is attached to the exoskeleton, shell or other external covering

Define Cardiac Muscles

Muscles that forms the wall of the heart. In vertebrates, this muscle consists of branched, generally uninucleate, striated muscle cells that are connected by intercalated discs. In invertebrates, may consist of striated and non-striated cells that may be endogenously active or controlled by neural output

Define Smooth (unstriated) muscle cells

Muscle that consists of small, spindled-shaped, uninucleate cells without striations. Thin actin filaments and thick myosin filaments are present, but aren't organized into sarcomeres

Define Muscle fiber

A term typically used to refer to skeletal or cardiac muscle cells, but sometimes applied to smooth muscle cells. Emphasizes the long, fibrous appearance of certain muscle cells.

Define myoblasts

Uninucleate embryonic muscle cells that fuse to form multinucleate muscle fibers

Define Myofibrils

A longitudinal component of a striated muscle cell that consists of a series of sarcomeres and extends the length of the cell

Define what the A and I bands are

A band:

- In striated muscle, the region of a sarcomere that spans the length of the thick filaments

- It includes the H zone and regions on both ends where thick and thin filaments overlap

I band:

- In striated muscle, a region of two sequentially adjacent sarcomeres that includes only thin filaments and is bisected by the Z disc; it shortens during contraction

Give a brief description of what and where the Z disc, H zone(band) and M line are on the myofibril

Z discs: In striated muscle, a web of accessory proteins at each end of the sarcomere

H zone (band): In striated muscle, a region at the center of a sarcomere that contains only thick filaments; shortens during contraction

M line: In muscle fibers, a web accessory of proteins at the center of a sarcomere that anchors the thick filaments and titin

Define sarcomere

The contractile unit of striated muscle that consists of contractile, regulatory, and cytoskeletal proteins.

Define Sarcolemma

The cell membrane of a muscle fiber

Define Myofilaments

Either two types of longitudinal components of sarcomeres. Thick filaments consist of polymerized myosin molecules, thin consist of polymerized actin molecules

What is the difference between a thick and thin filament?

Thick: polymers of myosin molecules in a muscle cells

Thin: polymers of G-actin monomers in muscle cells

Define Cross-bridges

The head of a myosin molecule interacting with actin molecules to produce muscle contraction by repeated oar-like power strokes. Each myosin molecule has two heads, each head has na actin-binding site and an enzymatic site that binds and hydrolyzes ATP to liberate energy to fuel each power stroke

Define Tropnin

In muscles, a protein consisting of 3 subunits that is associated with actin and tropomyosin on the thin filaments

Define Tropomyosin

In muscles, a coiled protein molecule that spans seven actin monomers on a thin filament and is associated with one troponin molecule

Define the excitation-contraction coupling

Linkage of the electrical excitation of the cell membrane with contractile activity by facilitation of the availability of Ca+2 in the cytoplasm

Define Tranverse/T-tubules

Fingerlike indentations of the cell membrane at regular intervals over the entire surface of a muscle cell. These conduct electrical excitation into the interior of the cell and are intimately associated with the sarcoplasmic reticulum

Define SR

The Sarcoplasmic Reticulum is a system of internal compartments in a muscle cell that envelops myofibrils and stores Ca+2 ions. The SR has calcium ATPase pumps that transport Ca+2 ions into its lumen and calcium channels that open in response to excitation along the associated transverse tubules

Define Intramuscular connective tissues

A complex network that physically holds various components of muscle in a discrete organ. It is primarily made up of collagen that surrounds individual muscle fibers, bundles of fibers, and the whole muscle exterior

Define Tendons

Connective tissue attachments of skeletal muscles to bones

Define Antagonistic (muscle) pairs

Two muscles or groups of muscles that perform coordinated opposing actions. When one muscle contracts to close the angle of a joint, its antagonist relaxes

Define Isometric contraction

A contraction in which a muscle does not shorten significantly as it exerted force (tension) against a load it cannot move

Define Isotonic contraction

A contraction in which the muscle force remains constant as the muscle changes length. (Rarely occurs in nature)

Define Cocentric/shortening Contraction

A contraction where the whole muscle shortens

Define Essentric/lengthing contraction

A contraction where the muscles are contracting as they lengthen

Define Load

The force against which a contracting muscle exerts an opposing force, the latter being referred to as muscle tension

Define Twitch

The mechanical response of muscle to a single action potential

Define Tetanus/tetanic contraction

Longer more sustained muscle contractions are the result of multiple twitches

Define Summation

In excitable cells, the addition of graded sub-threshold potentials. In muscle cells, the addition of twitches produced by high frequencies of action potentials

Define the length-tension relationship of muscle

The relationship between the length of a whole muscle or a sarcomere prior to stimulation and the tension developed during isometric contraction

Define load/force-velocity relationship

The principle that velocity of shortening of a muscle during isotonic contraction decreases as load increases

Define Work

Applying a force to an external object outside the body

Compare and contrast the types of contractions: Isometric, concentric, eccentric, isotonic, and tetanic

Isometric: Same length

Concentric: Shortening/pulling

Eccentric: Lengthening with a load

Isotonic: Same force applied over a long period time

Tetanic: Continual contraction

What are the 3 functions ATP performs during muscle contraction?

1. ATP binding to the cross-bridge is necessary for detachment of myosin from actin

2. Hydrolysis of ATP provides the energy necessary for bound cross-bridges to generate power strokes

3. Energy from hydrolysis of ATP drives the calcium pump that transports Ca+2 ions into the SR

What are the 3 biochemical mechanisms that muscle fibers use to make ATP?

1. Use of Phosphagen Creatine Phosphate

- high energy phosphate of creatine phosphate can be donated to ADP to produce ATP

2. Anaerobic Glycolysis

- Uses glycogen or glucose for fuel, and produces Lactic acid along with ATP

3. Aerobic Catabolism

- Can use all 3 classes of food stuff for fuel. Produces ATP mainly by oxidative phosphorylation

Define Tonic Muscle Fibers

Smooth muscle cells that constitute tonic smooth muscles; they maintain contractile force (tone) for long periods but don't generate spontaneous contractions or action potentials

Define Twitch muscle fibers

Skeletal muscle fibers that generate action potential when stimulated by motor neuron action potential and produce a contractile event called a twitch

Define motor unit

A motor neuron and all the muscle fibers it innervates