Animal Responses

What two systems is the nervous system split into?

The central nervous system and the peripheral nervous system.

What does the central nervous system consist of?

The brain and spinal cord.

What are the two functional systems of the peripheral nervous system?

The somatic nervous system and the autonomic nervous system.

What does the somatic nervous system control?

Conscious activities, such as running and playing video games.

What does the autonomic nervous system control?

Unconscious activities, such as digestion.

What are the two divisions of the autonomic nervous system?

The sympathetic nervous system and the parasympathetic nervous system.

What is the role of the sympathetic nervous system?

Prepares the body for action, known as the 'fight or flight' response.

What does the parasympathetic nervous system do?

Calms the body down.

What do sympathetic nerves do to heart rate?

Raise heart rate by secreting noradrenaline.

What effect do parasympathetic nerves have on heart rate?

Slow heart rate by secreting acetylcholine.

What is the difference between the anterior and posterior pituitary glands?

The posterior pituitary stores and releases hormones from the hypothalamus, while the anterior pituitary produces its own hormones.

Where is the cerebrum located and what is its function?

Largest part of the brain involved in hearing, vision, learning, and thinking.

Where is the hypothalamus located and what is its function?

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

Where is the medulla oblongata located and what does it control?

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

Where is the cerebellum located and what is its function?

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

What is a reflex?

Responses to the environment that are not processed by the brain.

Describe the blinking reflex process.

Sensory nerve endings detect touch, sending impulses to sensory neurons, then to relay neurons in the medulla, motor neurons contract muscles to close eyelids.

What are the two effectors in the blinking reflex?

Orbicularis oculi muscle (pulls eyes inward) and superior levator palpebrae (lowers the eyelid).

Explain the knee-jerk reflex.

Stretch receptors detect stretching, send impulses to motor neurons in the spinal cord, causing the quadriceps to contract and move the leg forward.

How do the nervous and hormonal systems coordinate 'fight or flight'?

Nerve impulses activate the hypothalamus, triggering hormonal release that increases heart rate and adrenaline secretion.

How does the nervous system help control heart rate?

The sinoatrial node generates impulses; the medulla controls heart rate based on internal stimuli.

How does the medulla respond to high blood pressure?

Sends impulses through the vagus nerve to secrete acetylcholine, decreasing heart rate.

How does the medulla respond to low blood pressure?

Sends impulses through the accelerator nerve to secrete noradrenaline, increasing heart rate.

How does the medulla respond to high/low pH levels?

High pH results in acetylcholine secretion; low pH results in noradrenaline secretion.

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

To determine if there is a significant difference between the means of two data sets.

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

If the calculated t-value is greater than the critical value at a probability of 5%.

What is the impact of adrenaline?

Increases heart rate, causes glycogen conversion to glucose, decreases blood flow to the gut, increases blood flow to heart and muscles, relaxes bronchioles.

What are skeletal muscles made from?

Large bundles of long cells called muscle fibers, with multi-nuclei and specialized organelles for contraction.

What are microfibrils made up of?

Bundles of thick myosin and thin actin myofilaments.

What does a microfibril look like under a microscope?

Dark A-bands with myosin filaments and light I-bands with actin filaments.

What are sarcomeres?

Short units that make up microfibrils.

What is the Z-line in muscle fibers?

The line that marks the ends of a sarcomere.

What can be found in the middle of each sarcomere?

The M-line, around which is the H-zone containing only myosin filaments.

Describe the sliding filament theory.

Myosin and actin filaments slide over each other to contract sarcomeres without shortening themselves.

What happens to the different bands in the sarcomere during contraction?

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

What are features of myosin filaments?

Globular heads that can move, binding sites for actin and ATP, and proteins troponin and tropomyosin aiding movement.

What happens to binding sites in resting muscles?

Tropomyosin blocks the actin-myosin binding sites, preventing contraction.

How does an action potential trigger muscle contraction?

It depolarizes the sarcolemma, causing calcium ion release, which binds to troponin and exposes binding sites.

How do calcium ions initiate contraction in skeletal muscle fibers?

They activate ATPase to release energy that moves myosin heads for contraction.

What is a sarcomere?

The contractile unit of a muscle fiber.

What is the sarcolemma?

The muscle cell membrane.

What are the structures of a microfibril?

I band (actin), H zone (myosin), Z line (end of sarcomere), A band (overlap of actin/myosin).

How does the actin-myosin binding occur?

Calcium ions bind to troponin, causing tropomyosin to move and expose binding sites for myosin heads.

What are differences between the NMJ and synapses?

NMJ releases only acetylcholine, connects motor neurons to skeletal muscles, and is always excitatory.

What causes muscle fatigue?

Calcium leaks, lack of ATP, oxygen depletion, lactate buildup, and synaptic fatigue.

What causes muscle cramps?

Lactic acid buildup, ATP depletion, and ion imbalance.

What is an antagonistic pair?

Two muscles working together, where one contracts and the other relaxes, such as biceps and triceps.

What is a synergist?

A muscle that aids a prime mover in movement and helps prevent rotation.

What are the three types of muscle?

Skeletal, cardiac, and smooth.

What are features of cardiac muscle?

Myogenic, has intercalated discs, packed with mitochondria, contracts rhythmically, and does not fatigue.

What are features of skeletal muscles?

Voluntary, cross-striations, quick contracting, and multiple nuclei.

What are features of smooth muscle?

Lacks cross-striations, spindle-shaped, found in hollow organs, contracts slowly.

How do antagonistic pairs work in the elbow?

Biceps lift the lower arm by contracting, while triceps relax to lower it; tendons and ligaments provide support.

How is the nervous system broken down?

Into the central nervous system and peripheral nervous system; peripheral is further divided into somatic and autonomic systems.