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BIOLOGY MODULE 5 > Plant and Animal Responses > Flashcards

Plant and Animal Responses Flashcards

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1
Q

what is the function of the autonomic nervous system?

A

controls involuntary responses, for example glands, smooth&cardiac muscles in blood vessels

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2
Q

What is the autonomic nervous system divided into?

A

sympathetic and parasympathetic

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3
Q

what are some functions and effects of the parasympathetic system?

A

conserves energy, rest and digest, decreases heart rate, constricts pupils, increases digestive activity

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4
Q

what are some functions and effects of the sympathetic system?

A

increases activity and is most active at times of stress, fight or flight, increases heart rate, dilates pupils and reduces digestive activity

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5
Q

what neurons do the sympathetic system use?

A

short preganglionic and long postganglionic

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6
Q

what neurons do the parasympathetic system use?

A

long preganglionic and short postganglionic

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7
Q

what system uses the neurotransmitter noradrenaline?

A

sympathetic system

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8
Q

what system uses the neurotransmitter actylcholine?

A

parasympathetic system

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9
Q

what does the hypothalamus control?

A

body temperature and osmoregulation

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10
Q

what does the posterior pituitary do?

A

linked to the hypothalamus by neurosecretory cells which pass down from the hypothalamus and are released into the blood

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11
Q

what does the anterior pituitary do?

A

produces its own hormones that are released into the blood in response to releasing factors

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12
Q

what are releasing factors?

A

hormones that need to be transported a short distance from the hypothalamus to the pituitary

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13
Q

what does the cerebrum control?

A

conscious thought, conscious actions, emotional responses, intelligence, reasoning, judgement, decision making and factual memory

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14
Q

what is the cerebellum important for?

A

coordination, posture, balance

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15
Q

what does the medulla oblongata control?

A

breathing and heart rate

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16
Q

what systems does the medulla oblongata contain?

A

cardiac centre (heart), vasomotor centre (circulation and blood pressure), respiratory centre (rate and depth of breathing)

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17
Q

what is a reflex action?

A

a response that doesn’t involve any processing by the brain

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18
Q

what do most reflex pathways consist of?

A

sensory> relay> motor

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19
Q

what is the reflex pathway of

the corneal reflex?

A

sensory nerve endings in the cornea are stimulated by touch, a nerve impulse is sent along the sensory neuron to a relay neuron which is then passed to motor neurons. They send the impulses to the effectors - facial muscles which causes blinking

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20
Q

how can we prevent blinking?

A

the cerebral cortex sends inhibitory signals to the motor centre in the pons, the myelinated neurons transmit action potentials that prevent the reflex from occurring

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21
Q

how does the knee-jerk reflex work?

A

stretch receptors in the quadriceps muscle detect that the muscle is being stretched, a nerve impulse travels along a sensory neuron which communicates directly with a motor neuron (no relay), this carries the impulse to the effector causing it to contract

22
Q

What is a physiological change during the fight or flight response? and what is its survival value?

A

pupils dilate - allows more light to enter eyes
heart rate and blood pressure increase - delivers more oxygen and glucose to muscles
errector pili muscles contract - sign of aggression
blood glucose levels increase - supplies energy for muscular contraction

23
Q

What is the process of the fight/ flight response?

A
  1. inputs feed into the sensory centres in the cerebrum
  2. the cerebrum passes signals to the association centres
  3. if a threat is recognised, the cerebrum stimulates the hypothalamus
  4. the hypothalamus increases activity in the sympathetic nervous system and stimulates the release of hormones from the anterior pituitary
24
Q

why is the endocrine system used in fight or flight?

A

because a prolonged response might be needed

25
Q

what is the mechanism of adrenaline action?

A
  1. adrenaline binds to the adrenaline receptorsm, this receptor is associated with a G protein on the inner surface of the plasma membrane, which is stimulated to activate the enzyme adenyl cyclase
  2. Adenyl cyclase converts ATP to cyclic AMP (cAMP), which is the second messenger inside the cell
  3. cAMP causes an effect inside the cell by activating enzyme action. The precise effect depends upon the cell that the adrenaline has bound to
26
Q

corticotropin-releasing hormone causes the release of what hormone?

A

adrenocorticotropic hormone (ACTH)

27
Q

Thyrotropin- releasing hormone (TRH) causes the release of what hormone?

A

thyroid-stimulating hormone (TSH)

28
Q

what are the roles of the circulatory system?

A

transport of oxgen and nutrients to tissues, removal of waste products, transport of urea from the liver to the kidneys, distribute heat around the body

29
Q

how can the heart action be modified?

A

raising or lowering the heart rate, altering the force of contractions, altering the stroke volume

30
Q

what does it mean that the heart is myogenic?

A

can initiate its own beat at regular intervals

31
Q

what does the SAN do?

A

initiates a wave of excitation to override the myogenic action of the cardiac muscle

32
Q

what is the typical frequency of excitation?

A

60-80 per minute

33
Q

Action potentials sent down the accelerans nerve have what effect?

A

cause the release of the neurotransmitter noradrenaline which increases heart rate

34
Q

Action potentials sent down the vagus nerve have what effect?

A

cause the release of the neurotransmitter acetylcholine which reduces heart rate

35
Q

what do stretch receptors do?

A

detect movement of the limbs, these send impulses informing that more oxygen might be needed (increase heart rate)

36
Q

what do chemoreceptors do?

A

monitor pH of the blood, when we exercise, the muscles produce more carbon dioxide - some of this reacts with water to produce carbonic acid, this reduces pH and makes transport of oxygen more difficult, this change is detected by chemoreceptors which send action potentials to the CV centre (increase heart rate)

37
Q

what are characteristics of smooth muscle?

A

contracts slowly and regularly, controlled by the autonomic system and is found in the walls of tubular structures (blood vessels)

38
Q

what are characteristics of cardiac muscle?

A

cells are joined by intercalated discs, contracts and relaxes continuously

39
Q

what are characteristics of skeletal muscle?

A

arranged in antagonistic pairs, contracts quickly and powerfully

40
Q

what is the neuromuscular junction?

A

the gap between the nervous system and the muscle, it is similar to a synapse

41
Q

what is the process of stimulation of contraction?

A
  1. Action potentials arriving at the end of the axon open calcium ion channels in the membrane. Calcium ions flood into the end of the axon
  2. Vesicles of acetylcholine move towards and fuse with the end membrane
  3. Acetylcholine molecules diffuse across gap and fuse with receptors in the sarcolemma
  4. opens sodium ion channels, allowing sodium ions to enter the muscle fibre, causing depolarisation of the sarcolemma
  5. wave of depolarisation spreads along the sarcolemma and down transverse tubules into the muscle fibre
42
Q

what is a motor unit?

A

when all muscle fibres contract together, providing a stronger contraction

43
Q

what is the structure of a myofibril?

A

thin filaments are aligned to make the light band (actin) and thick filaments make up the dark band (myosin)

44
Q

What is the composition of a thin filament in a myofibril?

A
  • two chains of actin twisted together
  • molecule of tropomyosin wrapped round this
  • troponin molecules attached to tropomyosin
45
Q

what does troponin bind to?

A

one binds to actin, one to tropomyosin and the third to calcium (when it’s available)

46
Q

What is the composition of a thick filament in a myofibril?

A

consists of a bundle of myosin molecules, each has two protruding heads which can bind to actin

47
Q

what is the sliding filament hypothesis?

A

The sliding action is caused by the myosin heads, when the muscle is stimulated, the tropomyosin is moved aside, exposing the binding sites on the actin. The myosin heads attach to the actin and move, causing the actin to slide past the myosin

48
Q

how is a contraction controlled in the myofibril?

A
  1. When the muscle is stimulated, the action potential passes along the sarcolemma and down the transverse tubules (t-tubules) into the muscle fibre
  2. The action potential is carried to the sarcoplasmic reticulum, which stores calcium ions and causes the release of calcium ions into the sarcoplasm
  3. The calcium ions bind to the troponin, which alters the shape pulling the tropomyosin aside. This exposes binding sites on the actin
  4. Myosin heads bind to the actin, forming cross-bridges between the filaments
  5. The myosin heads move, pulling the actin filament past the myosin filament
  6. The myosin heads detach from the actin and can bind again further up the actin filament
49
Q

what is the role of ATP during muscle contraction?

A
  1. The myosin head attaches to the actin filament, forming a cross bridge
  2. The myosin head moves (tilts backwards), causing the thin filament to slide past the myosin filament. This is the power stroke. During the power stroke ADP and Pi are released from the myosin head
  3. After the power stroke, a new ATP molecule attaches to the myosin head, breaking the cross bridge
  4. The myosin head then returns to its original position (forward) as the ATP is hydrolysed, releasing energy to make this movement occur. The myosin head can now make a new cross bridge further along the actin filament
50
Q

what are the three ways that the supply of ATP is maintained?

A

aerobic respiration, anaerobi respiration and creatine phosphate

51
Q

how does creatine phosphate maintain the supply of ATP?

A

creatine Phosphate in the sarcoplasm acts as a reserve store of phosphate groups - the phosphate can be transferred from the creatine phosphate to ADP molecules - creating ATP quickly

BIOLOGY MODULE 5 (4 decks)

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