Science 10

Central Nervous System

Central Nervous System

• acts as the body’s control center

• coordinates the body’s activities

• made up of the brain and spinal cord

Impulses

travel through the neurons in your body to reach the brain.

Peripheral Nervous System

• made up of all the nerves that carry messages to and from the Central Nervous System

• Central Nervous System and Peripheral Nervous System work together to make rapid changes in your body in response to stimuli

2 parts of the Peripheral Nervous System

• Somatic Nervous System

• Autonomic Nervous System

Somatic Nervous System

relay information between the skin, skeletal muscles, and Central Nervous System

Responsible for carrying motor and sensory information

Somatic Nervous System

Is made up of nerves that connect to the skin, sensory organs, and skeletal muscle movements

Processes sensory information from external stimuli (hearing, touch, and sight)

Autonomic Nervous System

relays information from the Central Nervous System to the organs

Involuntary: you cannot consciously control these

Sympathetic Nervous System

controls in times of stress, such as the fight or flight response

Parasympathetic Nervous System

controls the body in times of rest

Neurons

the basic unit of structure and function in the Nervous System

cells that conduct impulses

Neurons

made up of dendrites, cell body, and axons

Dendrites

• receive impulses from many other axons

• branch-like extensions which the receiver impulses and carry them toward the cell body

Axons

• single extension of the neuron that carries impulses away from the cell body

• branches out an ending to send impulses to many different neurons

Cell Body

• also called the soma, is the spherical part of the neuron that contains the nucleus

• connects to the dendrites, which bring information to the neuron, and the axon, which sends info to other neurons

• when information is received from another neuron, the dendrites pass the signal to this

Types of Neurons

Sensory Neurons

Interneurons

Motor Neurons

Sensory Neurons

carry impulses from inside and outside the body to the brain and spinal cord

Interneurons

found within the brain and spinal cord, process incoming impulses and pass them onto motor neurons

Motor Neurons

carry impulses away from the brain and spinal cord

Six Main Sections of the Brain

• Cerebrum

• Cerebellum

• Diencephalon

• Midbrain

• Pons

• Medulla Oblongata

Cerebrum

• controls memory, intelligence, muscles, conscious activities

• divided into 4 lobes which are:

  • Frontal Lobe - reasoning and thought

  • Temporal Lobe - processes auditory information from the ears

  • Parietal Lobe - integrates sensory information

  • Occipital Lobe - processing visual information from the eyes

Cerebellum

• Is found between the cerebrum and the midbrain

• Two Structures:

  • Thalamus - directs sensory impulses to the cerebrum

  • Hypothalamus - controls and regulates temperature, appetite, water balance, sleep, and blood vessel constriction and dilation

  • Also controls emotions

Brainstem

• Made up of medulla oblongata, pons, ad midbrain

• controls involuntary activities such as breathing

• Also called the reptilian brain

Cerebral Cortex

Wrinkled countless folds and groove

Medulla Oblongata

• involuntary activities such as heart rate and breathing

• The lowest part of the midbrain

• Regulates heart and blood vessel function

• Center for respiration

Pons

• located below the midbrain (in the brainstem)

• Responsible for certain reflex actions such as chewing, tasting, and saliva production

Spinal Cord

• The link between the brain and the nerves in the rest of the body

• Divided into 4 regions:

  • Cervical

  • Thoracic

  • Lumbar

  • Spinal nerves

Afferent Spinal Nerves

Carries information from the body to the brain

Efferent Spinal Nerves

Carries information from the brain to the body

Afferent Sensory Neurons and Efferent Motor Nerves

Allows communication to happen between the nerves in the body in the central nervous system

Afferent Sensory Neurons

• Conducting inward

• Takes information from the nerves to the central nervous system

Efferent Motor Neurons

• Conducting outward

• Takes information from the central nervous system to the muscle nerves throughout the body

Nervous System

• Coordinates all activities of the body

• Responds and adapts to change

Nervous System

• Coordinates all activities of the body

• Responds and adapts to change

Endocrine System

• Collection of glands that produce hormones, that regulate metabolism, growth and development, tissue function, sexual function, reproduction, sleep

• Includes endocrine glands and hormones

Hormones

• Produces notable effect

• Chemicals secreted by endocrine glands

• Chemical messenger which targets a specific group of cells

Exocrine glands

• Release their secretions into ducts or tubes

• Secrete sweat, tears, saliva, milk, and digestive

Endocrine glands

• Are called ductless glands

• Releases hormones directly into the bloodstream

• Each hormone acts only on a certain kind of tissue called its target tissue

Parts of the Endocrine System:

• Pituitary

• Thyroid

• Parathyroid

• Adrenal

• Pancreas

• Thymus

• Testes

• Ovaries

Pituitary gland

• At the base of the brain and is no bigger than a pea, located behind the bridge of the nose

• Often called the master gland

• Stimulates growth and controls function of other glands

• Hormones released are oxytocin, vasopressin, growth hormone, ACTH (adrenocorticotropic), prolactin

• Round organ, the size of a pea (1cm in diameter)

• Secretes different hormones

  • Growth

  • Blood Pressure

  • Regulation of Pregnancy, etc.

Gigantism

Oversecretion of growth hormones

Dwarfism

Undersecretion of growth hormones

Thyroid

• Stimulating hormone ~ Stimulates thyroid

• Follicle-stimulating hormone ~ regulates puberty

• Luteinizing hormone ~ stimulates the production of estrogen & testosterone

• Bowtie size, located in the neck

• releases thyroxin

• Regulates metabolism

Oversecretion of Thyroxin

weight loss and nervousness

cretinism

Under secretion of thyroxin

Goiter

iodine deficiency in diet can cause

Parathyroid

• Control metabolism of calcium

• Necessary for normal nerve and muscle function, blood clotting, healthy bones, and teeth

• Back of thyroid gland

• Releases hormone (Parathyromone)

• Under secretion - results in nerve disorder, brittle bones, and blood clotting

Adrenal Glands

• also known as Kidney Hats

• Located at the top of each kidney

• Release cortisone and adrenaline

Cortisone

regulates carbohydrate, protein, and fat metabolism

Adrenaline

raises blood sugar levels, increases heartbeat, and breathing rates

Undersecretion of Adrenaline

results in the inability to deal with stress

Islet of Langerhans

• Located in the pancreas

• Secretes hormones - insulin and glucagon

Insulin

stimulates glucose uptake by cells

Glucagon

promotes the conversion of glycogen (animal-based carbohydrates) to glucose

Undersecretion of Insulin

results in high blood sugar which leads to diabetes

Diabetes Type 1

• Found in children and young adults; the body does not make enough insulin

• Frequent urination, unusual thirst, extreme hunger, unusual weight loss, extreme fatigue, and irritability (symptoms)

Diabetes Type 2

• The body does not produce enough insulin

• Any type 1 symptoms, frequent infections, blurred vision, cuts/bruises that are slow to help, tingling/numbness of hand (symptoms)

Positive Feedback

• Controls events that can be out of control and do not require continuous adjustment

• Rarely used to maintain homeostasis

negative feedback

• Act like a thermostat in a home

• Often used to maintain homeostasis

Testicle

• Pair of sperm-producing organs that maintain the health of the male reproductive system

• Testes are known as gonads

• their female counterpart is the ovaries

• Also, have the distinction of being an endocrine gland because it testosterone - a hormone that is vital to the normal development of male physical characteristics

• Located at the lower abdomen

• hormones secreted: androgen, testosterone

Pineal Gland

Mainly connects the endocrine and nervous system

Hypothalamus

Controls the pituitary gland by producing chemical

Parathyromone

Hormones released by the parathyroid

Thymus

• Enables the body to produce antibodies

• Under secretion - inability to deal with stress

Ovary

• Primary girl/woman reproductive organs

• Are a pair of ova-producing organs (produce egg cells) that maintain the health of the female reproductive system

• Produces or secrete estrogen, and progesterone – which are vital to normal reproductive development and fertility

• are the female gonads

• Located in the lower abdomenMaintain the health of the female reproductive system

Vulva

the external female reproductive organs

External Female Structures

• Mons Pubis

• Labia Majora

• Labia Minora

• Clitoris

• Vestibule

• Perineum

Mons Pubis

• rounded, soft fullness of subcutaneous fatty tissue, prominence over the symphysis pubis that forms the anterior border of the external reproductive organs.

• is covered with varying amounts of pubic hair.

Labia

• Rich in nerve endings and blood vessels (similar…)

• Protects internal organs against pathogens

• Functions in sexual arousal

Labia Majora

• is two rounded, fleshy folds of tissue that extend from the mons pubis to the perineum.

• protects the labia minora, urinary meatus, and vaginal introitus.

Labia Minora

• located between the labia majora, are narrow.

• lateral and anterior aspects are usually pigmented

• inner surfaces are similar to the vaginal mucosa, pink, and mois.

• rich vascularity.

Clitoris

• the term comes from a Greek word meaning key.

• erectile organ.

• it’s rich in vascular, and highly sensitive to temperature, touch, and pressure sensations

• small knob of tissue above & in front of the vaginal opening

• rich supply of nerve endings & blood vessels

• important in sexual arousal

Vestibule

• is an oval-shaped area formed between the labia minora, clitoris, and fourchette

• contains the external urethral meatus, vaginal introitus, and Bartholins glands

Perineum

• is the most posterior part of the external female reproductive organs.

• extends from the fourchette anteriorly to the anus posteriorly.

• composed of fibrous and muscular tissues that support pelvic structures.

Internal Female Structures

• Vagina

• Uterus

• Fallopian tubes

• Ovaries

Fallopian tubes

• The two tubes extended from the corner of the uterus to the ovary.

• runs in the upper free border of the broad ligament.

• length 8 to 14 cm average 10 cm

Fimbriae

• are fingerlike processes, one of these is longer than the other and adherent to the ovary.

• become swollen and almost erectile at ovulation.

Ovaries

• oval solid structure, 1.5 cm in thickness, 2.5 cm in width, and 3.5 cm in length respectively.

• Each weighs about 4–8 gm.

• is located on each side of the uterus, below and behind the uterine tubes

• Secrete estrogen & progesterone.

• Production of ova

Uterus

• is a hollow, pear-shaped muscular organ.

• measures about 7.5 X 5 X 2.5 cm and weighs about 50 – 60 gm.

• normal position is anteverted (rotated forward and slightly anti-flexed (flexed forward)

• divided into three parts

  • Cervix

  • Vaginal Opening

  • Hymen

Cervix

• a part of the uterus

• lowermost position of the uterus “neck”.

• length is about 2.5 to 3 cm.

• the os is the opening in the cervix that runs between the uterus and vagina

• .the upper part of the cervix is marked by the internal os and the lower cervix is marked by the external os.

Hymen

• Located just inside the vaginal opening

• Thin tissue stretching across the opening

• No known function; not always present

• Some females may be born w/o; usually has several holes

• Allows passage of menstrual flow

Vagina

• An elastic fibro-muscular tube and membranous tissue about 8 to 10 cm long or 4 - 5” long

• Lying between the bladder anteriorly and the rectum posteriorly

• Connects the uterus above with the vestibule below

• “Birth canal”

• Allows discharge of the menstrual flow

• As the female organs of coitus

• To allow passage of the fetus from the uterus