Module 5.3 - Animal Responses Flashcards
What is the role of the Mammalian Nervous System? (4)
- Detects changes in environment
- Allows for cell signalling between all parts of the body
- Coordinates effectors
- Deals with rapid responses
What are the two structural systems of the nervous system (2)
- Central Nervous System (CNS)
- Peripheral Nervous System (PNS)
What is the role of the CNS? (1)
- To coordinate responses to stimuli
What is the CNS composed of? (2)
- Brain
- Spinal Cord
What is the brain composed of? (1)
- Non-myelinated relay neuron (grey matter)
What is the spinal cord composed of? (3)
- Non-myelinated relay neuron (grey matter)
- Outer region of myelinated neurons (white matter)
- Vertebral column
What does the white matter do? (1)
- Carries action potential up and down spinal cord
What are the structures of the brain? (5)
- Hypothalamus
- Cerebrum
- Pituitary Gland
- Medulla Oblongata
- Cerebellum
Hypothalamus? (4)
- Involved in negative feedback
- Found beneath the middle part of the brain
- Maintains body temperature
- Produces hormones that control the pituitary gland
Cerebrum? (4)
- Largest part of the brain
- Involved in vision, hearing, learning and thinking
- Consists of two cerebral hemispheres connected via corpus callosum
- Cerebral cortex
What is the corpus callosum? (1)
- Major tracts of neurones
What is the cerebral cortex? (3)
- Thin outer layer of nerve bodies
- Highly folded
- Has three subdivisions
What are the three cerebral cortex subdivisions? (3)
- Sensory areas
- Association areas
- Motor areas
What are the sensory areas? (2)
- Receives action potential from sensory receptors
- Size of region is relative to the sensitivity of area
What are the association areas? (1)
- Compares sensory input with previous inputs to interpret signals and select responses
What are the motor areas? (3)
- Sends action potential to various effectors
- Size is relative to the complexity of movement
- Left side of brain controls right side of body
Pituitary gland? (4)
- Found beneath the hypothalamus
- Controlled by the hypothalamus
- It releases hormones and stimulates other glands
- Consists of two lobes
What are the two lobes of the pituitary gland? (2)
- Anterior gland
- Posterior gland
What is the role of the anterior gland? (1)
- Produces its own hormones in response to stress, growth and reproduction factors
What is the role of the posterior gland? (2)
- Produces specialised neurosecretory cells
- e.g. ADH
Medulla Oblongata? (5)
- At the base of the brain
- Controls autonomic nervous system
- Controls non-skeletal muscles
- Controls cardiac, vasomotor and respiratory centres
- Automatically controls breathing and heart rate
Cerebellum? (3)
- Coordinates muscles, balances and posture
- Receives information from sensory receptors and processes them
- Cerebellar cortex
What is the role of the cerebellar cortex? (3)
- Involved in conscious decision to contract voluntary muscles
- Judges position of objects and limbs
- Generates slight tension for using instruments and tools
Pons? (1)
- Connects cerebrum and cerebellum
Reflex actions? (2)
- Reflex actions do not require processing in the brain before coordination takes place
- Any impulse sent through a relay neurone can be overridden
How can impulses sent through a relay neurone be overridden? (1)
- Myelinated neurone gets to CNS before non-myelinated relay neurone
Knee jerk reflex? (4)
- Reflex to straighten your leg to help maintain posture and balance
- Stretch receptors in quadriceps muscles detects muscle being stretched
- Nerve impulses passes through sensory neuron to motor neuron through spinal cord
- Motor neuron sends impulse to effector in quadriceps muscle causing it to contract
Blinking reflex? (4)
- Reflex to close your eyes to prevent damage
- Sensory nerve ending in cornea is stimulated
- Nerve impulses passes through sensory neuron to relay neuron in CNS
- Motor neuron sends impulse to effector in orbicularis oculi muscles causing it to contract
What are the physiological changes that occur in response to the “fight or flight response”? (9)
- Pupil dilate
- Heart rate and blood pressure increases
- Vasoconstriction of digestive system
- Vasodilation of muscles in liver
- Increase in blood glucose
- Metabolic rate increases
- Erector pili muscles in skin contrast
- Ventilation rate & depth increases
- Endorphins released in the brain
Physiological changes: pupils dilate (2)
- Allows more light to enter eyes
- Retina becomes more sensitive
Physiological changes: heart rate and blood pressure increase (1)
- Allows more oxygen and glucose to be delivered to responding effectors and to remove CO2 & toxins
Physiological changes: vasoconstriction of digestive system & vasodilation of muscles in liver (1)
- Diverts blood flow away from metabolism to muscles to prepare for fight or flight response
Physiological changes: increase in blood glucose (1)
- Supplies energy for muscular contraction
Physiological changes: metabolic rate increases (1)
- Converts glucose to create forms of energy such as ATP
Physiological changes: erector pili muscles in skin contract (2)
- Hairs stand up
- Sign of aggression
Physiological changes: ventilation rate & depth increases (3)
- Increase in gas exchange
- More oxygen is respired
- More toxins removed
Physiological changes: endorphins released in the brain (2)
- Wounds inflicted in the fight or flight response do not prevent activity
- Decreases sensitivity to injuries
How does the sympathetic nervous system response to a potential threat? (5)
- Signals sent from hypothalamus are sent to the adrenal medulla
- Adrenaline is released
- Adrenaline binds to cells such as G-proteins which stimulates adenyl cyclase to converts ATP into cyclic AMP (cAMP)
- cAMP activates enzyme action
- Different cell have difference responses
What are the effects of the adrenaline? (4)
- Increases heart rate
- Stimulates glycogenolysis
- Vasoconstriction of digestive system & vasodilation of muscles in liver
- Erector pili muscles contract
What are the two trophic hormones released from the anterior pituitary? (2)
- Corticotropin releasing hormones (CRH)
- Thyrotropin (TRH)
What is the role of CRH? (2)
- Stimulates the release ACTH (Adrenocorticotropic)
- Increases the rate of metabolism
What is the role of TRH? (2)
- Stimulates the release of thyroid stimulating hormone (TSH)
- Increases the releases of thyroxine which increases the rate of metabolism
How is the pace of the heart rate controlled? (3)
- Pace altered by cardiovascular centre in medulla oblongata
- Atrial & ventricle are controlled by SAN
- Myogenic
What is the role of the sympathetic and parasympathetic nerves in altering the frequency of contractions? (2)
- Sympathetic nerve (accelerants) increases heart rate
- Parasympathetic nerve (vagus) decreases heart rate
How is the nervous system involved in controlling the heart rate? (3)
- Stimuli is detected by baroreceptors and chemoreceptors
- Impulses are sent to the medulla through the nerves which secretes neurotransmitters which binds to receptors on the SAN
- SAN which controls the contractions of the heart will alter the pace the heart rate
What are the baroreceptors and chemoreceptors? (2)
- Baroreceptors are stretch/pressure receptors & detects changes in blood pressure
- Chemoreceptors are chemical receptors & detect changes in O2 levels
What are the nerves that impulses are sent through to reach the medulla and what are their roles? (2)
- Accelerant nerve = secretes noradrenaline
- Vagus nerve = secretes acetylcholine
How do the neurotransmitters affect the SAN? (2)
- Noradrenaline increases heart rate
- Acetylcholine decreases heart rate
What is the role of the sympathetic nervous system? (2)
- Increases heart rate
- Dilates pupils
What is the role of the parasympathetic nervous system? (4)
- Decreases heart rate
- Constricts pupils
- Lowers ventilation rate
- Increases digestion
What are the differences between the sympathetic (S) and parasympathetic (P) nervous system? (6)
- S has many neurones whilst P has a few
- In S ganglia is positioned outside the CNS whilst in P it is within effector tissue
- In S the preganglionic neuron is short whilst in P it is long
- In S the postganglionic neuron is long whilst in P it is short
- S use noradrenaline whilst P use acetylcholine
- S increases activity whilst P decreases it
What are the structures of skeletal muscles? (8)
- Compromised of large bundles of long cells called muscles fibres
- Sarcolemma cell membrane
- Sarcoplasm cytoplasm
- Transverse (T) tubules
- Sarcoplasmic reticulum
- Lots of mitochondria
- Multinucleate
- Myofibrils
What are T tubules? (2)
- Bits of sarcolemma that fold inwards and stick to the sarcoplasm
- They help spread electrical impulses across all parts of muscle fibre
What is sarcoplasmic reticulum? (2)
- Internal membranes
- Store and release calcium ions
What are myofibrils? (3)
- Long cylindrical organelles
- Specialised for contraction
- Consists of two filaments
What are the two filaments of myofibrils? (2)
- Thick myosin filaments
- Thin actin filaments
Thick myosin filaments? (2)
- Made of myosin
- Dark bands under microscope
Thin actin filaments? (2)
- Made of actin
- Light bands under microscope
What do myofibrils look under a microscope? (4)
- Short units called sarcomeres
- Ends of sarcomere is Z-line
- Middle of sarcomere is M-line
- Around M-line is H-zone which only contains myosin fibres
What is the Sliding Filament Theory? (3)
- Myosin and actin filaments slide over each other to make the sarcomere contract
- Simultaneous contraction of many sarcomeres = myofibrils and muscle fibres contract
- Sarcomeres shorten in length
Myosin filaments? (2)
- They have globular heads that are hinged to move back and forth
- Myosin heads have binding sites for actin and ATP
Actin filaments? (2)
- Actin-myosin binding sites for myosin heads
- Tropomyosin and troponin are between actin filaments
Tropomyosin and troponin proteins? (2)
- Proteins that are attached to each other in actin filaments
- Help myofilaments move past each other
Role of tropomyosin? (2)
- When resting Actin-myosin binding site is blocked by tropomyosin
- Myofilaments can’t slide past each other as myosin head can’t bind to actin filaments
How is muscle contraction triggered? (2)
- Action potential
- Triggers influx of Ca2+
What are the steps in muscle contraction? (9)
- Sarcolemma depolarises
- T tubule depolarises
- Sarcoplasmic reticulum depolarises
- Sarcoplasmic reticulum releases stored Ca2+
- Ca2+ bind to troponin and changes its shape
- Troponin pulls tropomyosin out of actin-myosin binding site
- Myosin head binds to actin-myosin binding site and cross bridge forms
- Myosin head pulls actin filament in a rowing motion
- Myosin head reattaches to different binding site and cycle repeats
Role of Ca2+ in muscle contraction: (3)
- Ca2+ bind to troponin to change its shape
- Ca2+ activate ATPase which breaks down ATP to provide energy
- Cycle will continue as long as Ca2+ are present
Role of ATP in muscle contraction: (2)
- ATP moves myosin head and pulls actin filament along in a rowing motion
- ATP breaks the cross bridge and detaches myosin head from actin-myosin binding site
How is ATP synthesised? (3)
- Aerobic respiration
- Anaerobic respiration
- ATP-Creatine Phosphate (CP) System
Aerobic respiration for ATP synthesis: (2)
- Oxidative phosphorylation in mitochondria
- Good for long periods of low intensity exercise
Anaerobic respiration for ATP synthesis: (5)
- Glycolysis
- End product is pyruvate
- Pyruvate –> lactate
- Lactate build-up = muscle fatigue
- Good for short periods of hard exercise
ATP-Creatine Phosphate (CP) System for ATP synthesis: (7)
- Phosphorylating ADP
- ADP + CP = ATP + Creatine
- CP is stored in cells and generate ATP quickly
- CP runs our after a few seconds
- Good for short bursts of vigorous exercise
- Anaerobic
- Alactic
What are the neuromuscular junctions? (2)
- Synapses between neurones and muscles
- Uses acetylcholine which bind to nicotinic cholinergic receptors
Type of muscles: (3)
- Skeletal
- Involuntary
- Cardiac
Voluntary/Skeletal muscle? (6)
- Controlled consciously
- Many muscle fibres
- Many nuclei
- Has cross-striation
- Some contract quickly for speed and strength but fatigue quickly
- Some contract slowly for endurance and posture and fatigue slowly
Involuntary/Smooth muscle? (7)
- Unconsciously controlled
- No striped appearance
- Found in walls of hollow internal organs
- Contract for peristalsis
- One nucleus
- Spindle-shaped
- Contract slowly and don’t fatigue
Cardiac muscles? (8)
- Myogenic
- Found in walls of heart
- Made of muscle fibres connected by intercalated discs
- Low electrical resistance
- Branched for spread of nerve impulse quickly
- One nucleus
- Some cross-striation
- Contract rhythmically and don’t fatigue
What is an electromyography? (3)
- Attached electrodes to three muscles, one control
- Electrical signals detected by electrodes
- Generated reading is called electromyogram
