Biology chapter 25

locomotion

movement of an organism from one place to another

motile

An organism that moves from place to place

sessile

organism that remains in a fixed position

motor unit and motor neuron

consists of a single motor neuron with all the muscle fibers that it stimulates via neurotransmitter junctions

muscle fibers

neuromuscular junction

myofibrils

tubes that consist of a series of sarcomeres linked end-to-end at z-disc

sarcomere

contracting unit of the muscle fiber (z line to z line)

actin

thin filament

myosin

thick filament

exoskeleton-arthropods

located outside the body (spiders, crustaceans, insects)

endoskelton-vertebrates

located on the inside of the body

insertion

muscle contraction causes movement

origin

fixed and contraction do not cause movement

joint

location where bones meet

fixed joint

don’t allow movement

articulated joint

allow bones to move in relation to each other

homeostasis

maintenance of the internal environment of an organism

positive feedback

increases gap between the original and new level not common in human body

negative feedback

decreases the gap so the original level is restored

thermoreceptors

free nerve endings of sensory neurons that monitor body temp.

thermoregulation

control of core body temp. to keep close to a set point

vasoconstriction

contraction of the muscles causing narrowing of lumen and restriction in blood flow

vasodilation

relaxation of the muscles causing widen of lumen and increase of blood flow

osmoregulation

keeping the osmotic concentration of body fluids within narrow limits allows water and pressure to be controlled

osmotic concentration

water balance in medulla kidney

excretion

removal of toxic waste products made from the breakdown of amino acids

aquaporins

channel proteins that allow water to pass

compare and contrast cardiac and skeletal (striated) muscle cells

skeletal: composed of striated muscle fibers, contract when stimulated by a motor neuron, uses neurotransmitters. cardiac: forms the wall of the heart, striated and branches, shorter cells and one nucleus

discuss whether a striated muscle fiber is a cell

yes: has a cell membrane, contains cytoplasm, functions as a single unit, no: multinucleated, formed by fusion of many cells, very large/long compared to normal cells, doesn’t divide like normal cells

explain how the sliding filament theory causes a muscle contraction

state the role of the protein titin

elastic polypeptide that acts as a molecular spring, storing potential energy when it is stretched and releasing this energy when it recoils

explain why there needs to be antagonistic muscle pairs

allow controlled smooth reversible movement

titin functions

holds each myosin filament in the correct position in the center of six parallel actin filaments, prevents overstretching of the sarcomere

explain the internal and external intercostal muscles as an example of antagonistic muscle action to facilitate internal body movements

explain how a bone acts as a lever. include fulcrum, joint, muscle, and effort

A bone acts as a lever by rotating around a joint (fulcrum) when a muscle applies a pulling force (effort) via a tendon. This moves a load (body part or object), allowing movement but trading off force and distance depending on where the effort is applied.

define or give the function of the parts of a synovial joint: bones

provide an anchorage for muscles and ligaments and guide the types of movement that occur at a joint

define or give the function of the parts of a synovial joint: cartilage

tough, smooth tissue that covers bone at the joint to prevent friction, contact, and absorb shocks

define or give the function of the parts of a synovial joint: synovial fluid

fills a cavity in the joint between the cartilage and ends of bones to lubricate and prevent friction

define or give the function of the parts of a synovial joint: ligaments

tough cords of tissue with collagen that connect bone to bone and prevent movements that would dislocate or damage the joint

define or give the function of the parts of a synovial joint: joint capsule

tough ligamentous covering to the joint that seals it and holds the synovial fluid

define or give the function of the parts of a synovial joint: muscles

provide the forces that cause movement at the joint

define or give the function of the parts of a synovial joint: tendons

tough cords of tissue with collagen that attach muscle to bone

state and define the motions of ball-and-socket joint: protract

forward motion of bone away from midline

state and define the motions of ball-and-socket joint:retract

backward motion of bone towards midline

state and define the motions of ball-and-socket joint: abduct

moving a limb away from the midline

state and define the motions of ball-and-socket joint: adduct

moving a limb towards the midline

state and define the motions of ball-and-socket joint: rotate

turning a bone around its axis 

explain the adaptations for swimming in marine mammals: streamlining

marine mammals are shaped to minimize resistance to motion

explain the adaptations for swimming in marine mammals: adaptation of limbs to form flippers

used for steering instead of front legs

explain the adaptations for swimming in marine mammals: tail to form a fluke with up-and-down movement

lobes to left and right that increase thrust when the tail is moved up and down

explain the adaptations for swimming in marine mammals: blubber

provides buoyancy, allowing dolphins to cease moving and float below the surface during sleeping

explain the adaptations for swimming in marine mammals: blowhole

leading from larynx to upper surface of the head and used for marine mammals to breathe

state examples of homeostatic variables

body temperature, blood pH, blood glucose concentration, and blood osmotic concentration

explain the use of negative rather than positive feedback control in homeostasis

reverses deviations from the set point, keeping internal conditions stable and within a narrow range. Positive feedback would amplify changes, pushing equilibrium farther

explain the regulation of blood glucose levels using insulin and glucagon

When blood glucose is high, insulin causes cells to take in glucose and store it as glycogen, lowering blood sugar; when it is low, glucagon causes glycogen to be broken down into glucose, raising blood sugar.

list the characteristics, risks, prevention, and treatment of type 1 and type 2 diabetes: type 1

autoimmune disease arising from the destruction of beta cells by the body’s own immune system,

list the characteristics, risks, prevention, and treatment of type 1 and type 2 diabetes: type 2

inability to process or respond to insulin because of a deficiency of insulin receptors or glucose transporters on target cells, risk factors are sugary or fatty diets, obesity, lack of exercise

explain the process of thermoregulation as an example of negative feedback control: peripheral thermoreceptors

located in the skin to anticipate rates of heat loss from the body

explain the process of thermoregulation as an example of negative feedback control: hypothalamus

secretes thyrotropin-releasing hormone (TRH) that goes to the pituitary gland

explain the process of thermoregulation as an example of negative feedback control: pituitary gland

responds to TRH and secretes thyroid- stimulating hormone (TSH)

explain the process of thermoregulation as an example of negative feedback control: thyroxin

responds to TSH and releases the hormone thyroxin, which increases metabolic rate in cells

explain the process of thermoregulation as an example of negative feedback control: muscle

generate heat when they contract

explain the process of thermoregulation as an example of negative feedback control: adipose fat tissue

can generate heat at a rapid rate

explain the process of thermoregulation for humans: vasodilation

arterioles widen as circular muscles in the walls relax

explain the process of thermoregulation for humans: vasoconstriction

contraction of the muscles, causing narrowing of the lumen and restricting blood flow

explain the process of thermoregulation for humans: shivering

small, involuntary muscle contractions and relaxations are carried out at a rapid rate to generate heat

explain the process of thermoregulation for humans: sweating

secreted by glands in the skin and passes through narrow ducts to the skin surface

explain the process of thermoregulation for humans: uncoupled respiration in brown adipose tissue

energy released as heat from brown adipose fat tissue and not ATP

explain the process of thermoregulation for humans: hair erection

erector muscles can move hairs to stand up, but they do not trap air well enough to insulate the body

state that changes in blood supply to organs are in response to changes in activity.

what is the function of the kidney

its about osmoregulation and excretion

state the function of the following parts of the nephron in the kidneys: glomerulus

capillary bed under high pressure, and is the site of filtration

state the function of the following parts of the nephron in the kidneys: bowman’s capsule

cup-shaped structure that collects the fluid filtered from the blood

state the function of the following parts of the nephron in the kidneys: proximal convoluted tubule

twisted section with microvilli projecting into the lumen and many mitochondria

Explain the processes of ultrafiltration nephron. (first step of production of urine)

process by which various substances are filtered through the glomerulus from the blood into Bowman’s capsule

Explain the processes of reabsorption in the nephron.

process in which needed substances are returned to the blood

State the functions of the loop of Henle. Include the following:

Active transport of sodium ions in the ascending limb to maintain high osmotic concentrations in the medulla, Facilitating water reabsorption in the collecting ducts

Explain the process of osmoregulation by water reabsorption in the collecting ducts. Include the function of the following:

Osmoreceptors in the hypothalamus, Changes to the rate of ADH secretion by the pituitary gland, Aquaporins between cell membranes 

State the effect of the presence of ADH and the lack of ADH on the water reabsorption in the collecting ducts.

if osmotic concentration is too low (too much water in blood) no ADH is secreted and water stays in collecting duct (light colored urine)

Short Answer: Includes the roles of the loop of Henle, aquaporins, and ADH for the control of water reabsorption in the collecting duct.

The loop of Henle creates a concentration gradient in the medulla, allowing water to be reabsorbed by osmosis. ADH increases the permeability of the collecting duct by inserting aquaporins, so more water is reabsorbed into the blood when needed.

State the pathway that urine leaves the body.

renal pelvis, ureter, urinary bladder, urethra