science ☆

• network of nerves that connect the spinal cord and the brain to the rest of the body

• allow a stimulus-response reaction to occur among different organs

Nervous System

2 major sections of nervous system

• central nervous system

• peripheral nervous system

carry messages back and forth between the brain and spinal cord and the rest of the body

Peripheral Nervous System

receive, process, interpret, and send info thru electrical signals that neurons carry towards (PNS)

Central Nervous System

• fundamental units of nervous system

• translate external stimuli into electrical signals transmitted into the brain

Neurons

main part of the neuron where the nucleus is located

Cell body/soma

thick branch that trails behind the soma

Axon

smaller branch-like extensions, process electrical impulses before transmitting them to the axon.

Dendrites

• react to both external & internal stimuli

• pick up info from outside your body and deliver it to your central nervous system

Sensory Neurons

translate the info between sensory neurons and motor neurons

Interneurons

pick up info from central nervous system and transmit it thru nerves in the rest of your body

Motor Neurons

2 Main parts of CNS (central nervous system)

• brain

• spinal cord

major organ, reads info, and controls all functions of the human body

Brain

includes the cerebral cortex, which handles complex thinking, decision-making, and emotions.

Forebrain

helps coordinate movements, especially eye movements, and processes auditory and visual information.

Midbrain

includes the cerebellum, which coordinates movement and balance, and the brainstem, which controls vital functions like breathing, heart rate, and digestion

Hindbrain

largest part of the brain, responsible for higher brain functions such as thought, voluntary movement, language, reasoning, perception, and memory.

Cerebrum

located underneath the cerebrum, responsible for coordinating voluntary movements, balance, and posture.

Cerebellum

located at the base of the brain and connects the brain to the spinal cord. It regulates many basic life functions such as breathing, heart rate, blood pressure, and digestion.

Brainstem

responsible for transmitting the electrical signals from brain to the nerves that extend to different parts of the body

Spinal Cord

2 Major Divisions of PNS (peripheral nervous system)

• somatic

• autonomic nervous system

• voluntary functions

ex. touch, sight, and hearing.

Somatic Nervous System

• involuntary actions

ex. heart rate, digestion, and breathing.

Autonomic Nervous System

3 divisions of Autonomic Nervous System

• sympathetic nervous system

• parasympathetic nervous system

• enteric nervous system

• This is like the body's "fight or flight" response, which kicks in during times of stress or danger.

Sympathetic Nervous System

• responsible for the body's "rest and digest" response, calming the body down after a stressful situation.

Parasympathetic Nervous System

• operates independently of the brain and spinal cord, managing processes like swallowing and the movement of food through the digestive system

Enteric Nervous System

It consists of glands that produce hormones, which are chemical messengers that regulate various bodily functions.

Endocrine System

chemical signals that instruct your internal organs to perform tasks

Hormones

sends signals to other glands to release hormones, and regulates body temperature, hunger, thirst, and other basic functions.

Hypothalamus

produces hormones that regulate growth, reproduction, and other glands.

Pituitary Gland

produces melatonin, which regulates sleep-wake cycles.

(helps you sleep and wake up at the right times)

Pineal Gland

controls calcium levels in the blood

Parathyroid Gland

produces hormones that control metabolism, energy levels, and growth.

(helps regulate your weight and energy)

Thyroid Gland

produces hormones that help develop the immune system, especially in children.

(helps your body fight off infections and diseases)

Thymus

produce hormones like adrenaline and cortisol, which help the body respond to stress.

Adrenal Glands

produces insulin and glucagon, which regulate blood sugar levels.

Pancreas

• body's female hormone

• produce estrogen and progesterone, which regulate menstrual cycles and female characteristics.

Ovaries

• body’s male hormone

• produce testosterone, which regulates male characteristics and reproductive functions. (control sperm production)

Testes

• consists of interconnected sexual organs and tissues that function in unison for production, storage, and development of reproductive cell.

Reproductive System

Oval-shaped organ which is responsible for the production and storage of billion of sperm cells

Testis or Testicle

Thin external pocket that houses the testes

Scrotum

This is where sperm mature and are stored.

Epididymis

Passageway for semen, carries mature sperm from the epididymis to the urethra

Vas Deferens

These glands produce fluid that nourishes energy and helps sperm move.

Seminal Vesicles

Produces fluid that protects sperm and helps with ejaculation.

Prostate

These glands produce fluid that lubricates the urethra.

Bulbourethral Glands or Cowper’s Gland

Tubes that carry sperm from the vas deferens to the urethra. They mix sperm with fluids from the seminal vesicles and prostate gland before ejaculation.

Ejaculatory Ducts

Tube that carries urine and semen out of the body.

Urethra

Male reproductive organ involved in sexual intercourse.

Penis

Retractable fold of skin covering the tip of the penis.

Foreskin

generation of cells inside the testes and the epididymis

Spermatogenesis

3 main parts of sperm cell

• head

• midpiece

• tail

Contains the genetic material (DNA) needed for fertilization.

Head

Contains mitochondria providing energy for movement.

Midpiece

Propels the sperm forward, allowing it to swim towards the egg for fertilization.

Tail

two almond-shaped organs located on both sides of female reproductive system

Ovaries

outer covering

follicles

protects the structure of ovaries

primordial follicle

formation of egg cells,

Oogenesis

connect ovaries to the central part of reproductive system

Fallopian Tubes

• This is a hollow, muscular organ in the female reproductive system.

• It's where a fertilized egg implants and grows into a baby during pregnancy.

Uterus

• located below the cervix, serving as a passageway for menstrual flow and childbirth.

Vagina

the vagina is covered by this thin, mucous membrane

Hymen

• hormone produced by the pituitary gland.

• In females, it triggers ovulation (the release of an egg from the ovary) and stimulates the production of progesterone.

• Think of it as the hormone that helps prepare the body for potential pregnancy.

Luteinizing hormone

• This is another hormone produced by the pituitary gland.

• In females, it stimulates the growth and development of ovarian follicles (sacs containing eggs) during the menstrual cycle.

• Think of it as the hormone that kickstarts the process of egg maturation and release.

Follicle-stimulating hormone