Exam 2 - The nervous system

cranial nerves

spinal nerves

What are the 2 organ systems that coordinate closely in all physiological processes to maintain homeostasis?

Nervous system & Endocrine system

Responses are fast and brief, and can be very specific in target

Nervous system

Responses are slower but last longer, often have more general effects

Endocrine system

What’s the most complex organ system?

nervous system

What are the three main functions of the nervous system?

Monitors the body’s internal and external environments.

Receives and integrates sensory information from the environment.

Initiates and coordinates both voluntary and involuntary physiological responses to maintain homeostasis.

CNS

Central nervous system

What parts of the body does cns includes?

The brain and the spinal cord

What are the main functions of the central nervous system?

Receives, integrates, processes and coordinates sensory input (sensation).

Initiates and sends motor commands (movement)

The location of higher functions (intelligence, memory, and emotion)

PNS

Peripheral nervous system

What makes up the peripheral nervous system (PNS) and what is its role?

It consists of all neural tissue found outside of the brain and spinal cord and serves as the only physical connection between the CNS and the rest of the body.

Which nervous system includes all neural tissue outside the brain and spinal cord?

PNS

Afferent division

Delivers sensory information from peripheral receptors to the CNS.

Efferent division

Sends commands to peripheral organs from the CNS

What is the somatic nervous system responsible for?

Voluntary & conscious movement of the body

What is the autonomic nervous system responsible for?

Responsible for involuntary functions.

What kind of control does ANS has?

Unconscious control of smooth muscles, cardiac muscles, and glands.

“Fight or flight” response

Sympathetic division

“Rest and digest” response

Parasympathetic division

Which division of the autonomic nervous system is responsible for effects such as increased heart rate and pupil dilation?

The sympathetic division

Which division of the autonomic nervous system is responsible for effects such as decreased heart rate and an increase blood flow to intestines?

The Parasympathetic and (enteric) division

What does the efferent division of the peripheral nervous system do?

It carries motor commands from the CNS to peripheral tissues and systems.

What are the two main divisions of the efferent nervous system?

The somatic nervous system (SNS) and the autonomic nervous system (ANS).

Which effectors are controlled by the somatic nervous system?

Skeletal muscles.

Is the somatic nervous system under voluntary or involuntary control?

Voluntary control

Which effectors are controlled by the autonomic nervous system?

Smooth muscle, cardiac muscle, glands, and adipose tissue.

Is the autonomic nervous system under voluntary or involuntary control?

Involuntary control.

What are the two divisions of the autonomic nervous system?

Parasympathetic division and sympathetic division.

Which division of the ANS is responsible for “rest and digest” functions?

The parasympathetic division.

Which division of the ANS is responsible for “fight or flight” responses?

The sympathetic division.

What are the four major tissue types?

Nervous, muscle, epithelial, and connective.

What’s the function of neurons?

Transmit and receive electrical nerve impulses.

What cell provides rapid communication?

Neurons ( Nerve Cells)

What are glial cells (neuroglia)?

Nonneuronal cells of the nervous system that support neurons.

How do glial cells compare in number to neurons?

They outnumber neurons by about 10-fold.

Which glial cells form myelin in the CNS?

Oligodendrocytes.

Which glial cells form myelin in the PNS?

Schwann cells

Which type of glial cell provides structural and metabolic support for neurons?

Astrocytes

Which type of glial cell acts as immune defense in the CNS?

Microglia

Which glial cells line the ventricles of the brain and produce cerebrospinal fluid (CSF)?

Ependymal cells

Consists of a nerve cell body and its processes (axon and dendrites)

Neurons

What does Axon do?

Conducts nerve impulses away from cell body.

How many axons exist per neuron?

One

Dendrites , perform what function?

Conducts nerve impulses towards cell body

Many Dendrites per neuron=

Multipolar

Does dendrites increase or decrease cell surface area?

Increases

What is the role of sensory (afferent) neurons?

They receive information from sensory receptors and relay it to the CNS.

What are the structural types of sensory neurons?

Pseudounipolar (general senses) and bipolar (special senses).

What is the role of motor (efferent) neurons?

They carry instructions away from the CNS to effectors.

What are effectors in relation to motor neurons?

Peripheral targets of motor commands (e.g., muscles, glands).

What is the structural type of motor neurons?

Multipolar neurons.

Where are interneurons located?

Entirely within the CNS.

What is the function of interneurons?

They interconnect other neurons and process information.

What is the structural type of interneurons?

Multipolar neurons.

What are neurons?

Nerve cells of the nervous system.

What are the two possible forms of neurons regarding myelin?

Myelinated or unmyelinated.

What type of molecule is myelin made of?

A sphingolipid.

What is the function of myelin?

It acts as electrical insulation, speeding up signal transmission.

Which glial cells produce myelin in the peripheral nervous system (PNS)?

Schwann cells.

How do Schwann cells form myelin?

The myelin-containing cell body wraps around axons of neurons.

What is the gap between Schwann cells called?

Node of Ranvier

Which glial cells produce myelin in the central nervous system (CNS)?

Oligodendrocytes.

What are astrocytes and what is their main role?

“Star-shaped” glial cells that provide structural support and help transport molecules from blood capillaries to neurons.

What important barrier are astrocytes involved in?

The blood-brain barrier.

What are ependymal cells and where are they found?

“Lining” cells—simple columnar epithelial cells that line the ventricles of the brain.

What do ependymal cells produce?

Cerebrospinal fluid (CSF).

What are microglia and what is their function?

“Small” glia that act as resident immune cells (macrophages) of the CNS with a phagocytic role.

What is the resting membrane potential (RMP)?

The difference in electrical charge between the inside and outside of a cell.

Which cells can manipulate their resting membrane potential?

Nerve and muscle cells.

What causes the resting membrane potential?

Unequal distribution of Na⁺ (more outside) and K⁺ (more inside).

What maintains the resting membrane potential, and how?

The Na⁺/K⁺ ATPase pump, which actively moves 3 Na⁺ out and 2 K⁺ in per ATP used.

What is membrane depolarization?

When Na⁺ channels open, Na⁺ rushes in, and the inside of the cell becomes more positive.

What is membrane repolarization?

When K⁺ channels open, K⁺ leaves, restoring the inside of the cell to a negative charge.

What is hyperpolarization?

When the membrane potential becomes more negative than the resting potential.

What is the spinal cord a continuation of?

The medulla oblongata.

How do spinal nerves arise?

In left and right pairs from between each vertebra.

How many spinal nerve pairs are in the cervical region of a dog?

8 pairs (even though there are 7 vertebrae).

How many spinal nerve pairs are in the thoracic region of a dog?

13 pairs

How many spinal nerve pairs are in the lumbar region of a dog?

7 pairs

How many spinal nerve pairs are in the sacral region of a dog?

3 pairs (from fused vertebrae).

How many spinal nerve pairs are in the caudal region of a dog?

6–7 pairs (from ~20 vertebrae).

What is white matter composed of?

Bundles of myelinated nerve axons.

What is gray matter composed of?

Nerve cell bodies and their processes.

What are the two main horns of gray matter?

Dorsal horn and ventral horn.

Where do afferent sensory nerves enter the spinal cord?

Through the dorsal root.

Where do efferent motor nerves exit the spinal cord?

Through the ventral root.

What are the main functions of the cerebrum?

Conscious thought, sensations, voluntary movement, intellectual functions, and memory storage/processing.

What structures are included in the interbrain (diencephalon)?

Epithalamus, thalamus, hypothalamus, and pituitary gland.

What are the main functions of the brain stem?

Processing centers, relay station, and control of autonomic functions.

What is the role of the cerebellum?

Involuntary maintenance of posture, muscle control, and balance.

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