Animal Responses

What is the central nervous system (CNS) made up off?

Made up of the brain and the spinal cord.

What is the peripheral nervous system (PNS) made up off?

Made up of the nerves that connect the CNS to the rest of the body.

What does the somatic nervous system control?

Controls conscious activities, e.g., running and playing video games.

What does the autonomic nervous system control?

Controls unconscious activities, e.g., digestion.

What is the function of the sympathetic nervous system?

Prepares the body for action; the 'fight or flight' system.

What is the function of the parasympathetic nervous system?

Calms the body down.

What do sympathetic nerves do?

Raises heart rate by secreting noradrenaline.

What do parasympathetic nerves do?

Slows heart rate by secreting acetylcholine.

What is the function of the posterior pituitary gland?

Only stores and releases hormones (ADH and oxytocin) sent from the hypothalamus.

What is the function of the anterior pituitary gland?

Produces and releases its own hormones.

Where is the cerebrum and what is its function?

Largest part of the brain, divided into cerebral hemispheres, involved in hearing, vision, learning, and thinking.

Where is the hypothalamus and what is its function?

Found beneath the middle part of the brain; monitors blood temperature and produces hormones that control the pituitary gland.

Where is the medulla oblongata and what is its function?

At the base of the brain, controls breathing rate and heart rate automatically.

Where is the cerebellum and what is its function?

Underneath the cerebrum; important for muscle coordination, posture, and balance.

What is a reflex?

Responses to the environment not processed by the brain.

Step 1 of the blinking reflex?

Sensory nerve endings in cornea are stimulated by touch.

Step 2 of the blinking reflex?

Impulse sent along sensory neuron to relay neuron in the medulla oblongata.

Step 3 of the blinking reflex?

Impulse passed to motor neurons in the oculomotor nerve.

Step 4 of the blinking reflex?

Oculomotor nerve sends impulses to superior levator palpebrae.

Step 5 of the blinking reflex?

Motor neurons send impulses to orbicularis oculi muscles from the facial nerve root.

Step 6 of the blinking reflex?

Muscles contract, causing eyelids to close quickly.

What is the function of the orbicularis oculi muscle?

Pulls eyes inward during blinking reflex.

What is the function of the superior levator palpebrae?

Lowers the eyelid during blinking reflex.

Step 1 of the knee-jerk reflex?

Stretch receptors in quadriceps detect muscle stretching.

Step 2 of the knee-jerk reflex?

Impulse passed along sensory neuron directly to motor neuron in the spinal cord.

Step 3 of the knee-jerk reflex?

Motor neuron carries impulse to quadriceps muscle.

Step 4 of the knee-jerk reflex?

Quadriceps muscle contracts, causing lower leg to move forward.

Step 1 of nervous/hormonal coordination in 'fight or flight'?

Nerve impulses arrive at the hypothalamus, activating hormonal and sympathetic nervous systems.

Step 2 of nervous/hormonal coordination in 'fight or flight'?

Pituitary gland releases ACTH, causing adrenal cortex to release steroidal hormones.

Step 3 of nervous/hormonal coordination in 'fight or flight'?

Sympathetic nervous system activated, triggering adrenaline release from adrenal medulla.

How does fight or flight affect heart rate?

Increases to pump blood faster.

How does fight or flight affect muscles around the bronchioles?

Relax, so breathing is deeper.

How does fight or flight affect glycogen?

Is converted to glucose, more respiration.

How does fight or flight affect Erector pili muscles?

Contract, making hairs stand on end.

How does fight or flight affect arteriole muscles?

It dilates

What does the sinoatrial node (SAN) do?

Generates electrical impulses that cause cardiac muscles to contract.

How is the rate at which the SAN fires (heart rate) controlled?

Unconsciously controlled by the medulla.

How are internal stimuli detected in the nervous system's heart rate control?

Detected by pressure and chemical receptors (e.g., baroreceptors).

Medulla's response to high blood pressure?

Detected by baroreceptors, impulses sent to medulla, which sends impulses along the vagus nerve, secreting acetylcholine.

Medulla's response to low blood pressure?

Detected by baroreceptors, impulses sent to medulla, which sends impulses along the accelerator nerve, secreting noradrenaline.

Medulla's response to high pH levels?

Detected by chemoreceptors, impulses sent to medulla, which sends impulses along the vagus nerve, secreting acetylcholine.

Medulla's response to low pH levels?

Detected by chemoreceptors, impulses sent to medulla, which sends impulses along the accelerator nerve, secreting noradrenaline.

What is the student's t-test used for?

Used to find significant difference between means of 2 data sets.

When do you reject the null hypothesis in the student's t-test?

Obtained value > critical value at p < 0.05.

What are the many impacts of adrenaline?

Increases heart rate and stroke volume, converts glycogen to glucose, affects blood flow, and widens bronchioles.

How does adrenaline affect heart contraction?

Heart contracts more and harder.

What are muscle fibres?

Large bundles of long cells.

What is the sarcolemma?

Cell membrane of muscle fibre cells.

What are transverse (T) tubules?

Folds of the sarcolemma that help spread electrical impulses.

What is the sarcoplasmic reticulum function

Stores and releases calcium ions for muscle contraction.

Why do muscle fibres have lots of mitochondria?

Provides ATP for muscle contraction.

How are muscles multinucleate?

Contain many nuclei.

What are myofibrils?

Cylindrical organelles specialized for contraction.

What do myofibrils contain?

Bundles of thick (myosin) and thin (actin) myofilaments.

What are thick myofilaments made of?

Made of the protein myosin.

What are thin myofilaments made of?

Made of the protein actin.

What are A-bands (dark bands)?

Contain thick myosin filaments and overlapping actin filaments.

What are I-bands (light bands)?

Contain only thin actin filaments.

What are sarcomeres?

Short units that make up microfibrils.

What is the Z-line?

Marks the ends of a sarcomere.

What is the M-line?

The middle of the myosin filaments.

What is the H-zone?

Contains only myosin filaments.

What happens during the sliding filament theory?

Actin and myosin filaments slide over each other to contract sarcomeres.

What happens to the bands in the sarcomere as it contracts?

A-band stays the same length, I-band and H-zone get shorter.

What are some features of myosin filaments?

Globular heads that bind to actin and ATP.

Name components found between actin filaments.

They’re made of troponin and tropomyosin which help the myofilaments move past each other.

What happens to the binding sites of resting muscles?

Actin-myosin binding site is blocked by tropomyosin.

What is the first step of how an action potential triggers muscle contraction?

Depolarizes the sarcolemma.

What is the second step of how an action potential triggers muscle contraction?

Spreads down T tubules to sarcoplasmic reticulum.

What is the third step of how an action potential triggers muscle contraction?

Releases stored calcium ions into the sarcoplasm.

What is the fourth step of how an action potential triggers muscle contraction?

Ca2+ ions bind to troponin, exposing the actin-myosin binding site.

What do ATP do in how an action potential triggers muscle contraction?

Myosin detaches itself and reattaches to a different binding site.

What happens when the muscle stops being stimulated?

Calcium ions are moved back into the sarcoplasmic reticulum.

What is a neuromuscular junction?

Synapse between a motor neuron and a muscle cell that uses acetylcholine (ACh).

What happens when a chemical blocks neurotransmitter release?

May prevent action potential, affecting muscles involved in breathing.

What is skeletal muscle?

Voluntary muscle with cross-striations, used for speed, strength, endurance, and posture.

What is involuntary muscle?

Involuntary muscle without striations, found in walls of internal organs, contracts slowly.