Rabbit: excretory, nervous and reproductive systems
A rabbit removes urea through two kidneys, is controlled by a brain, spinal cord and nerves, and has separate sexes with internal fertilisation and young born alive.
Excretory system: the path of urine
Each kidney is bean-shaped and dark red, with an outer **cortex** and an inner **medulla**. Its working units, the **nephrons**, filter **urea** and extra water out of the blood. The rabbit is **ureotelic**: its main nitrogen waste is urea.
Nervous system
- Central nervous system: the brain, protected by the skull (cranium), and the spinal cord, protected by the backbone.
- Both are covered by three membranes, the meninges: the outer dura mater, the middle arachnoid and the inner pia mater.
- Forebrain: olfactory lobes (smell), the cerebrum of two cerebral hemispheres joined by the corpus callosum, and the diencephalon.
- Midbrain: four optic lobes (corpora quadrigemina), linked with sight and hearing.
- Hindbrain: the cerebellum (balance), the pons and the medulla oblongata (breathing, heartbeat), which continues as the spinal cord.
- Peripheral nervous system: 12 pairs of cranial nerves and 37 pairs of spinal nerves.
Reproductive system
| Part | Male | Female |
|---|---|---|
| Gonads | A pair of oval testes in scrotal sacs; each has many seminiferous tubules that make sperm | A pair of small, almond-shaped ovaries in the abdomen, behind the kidneys |
| Ducts | Epididymis (stores sperm) → vas deferens → urethra → penis | Fallopian tubes (oviducts) with a funnel-shaped opening → uterus → vagina → vestibule → vulva |
| Accessory glands | Prostate, Cowper's and perineal glands; their secretions help the sperm | Cowper's glands and perineal glands |
Fertilisation and development
The sexes are separate, and males and females look slightly different. Fertilisation is internal: sperm meet the egg in the fallopian tube. The embryo grows in the uterus and gets food and oxygen from the mother through the placenta. The young are born alive (viviparous), and the mother feeds them milk from her mammary glands.
How to draw the excretory system of a rabbit
- 1Draw two bean-shaped kidneys side by side, with their notches (hilum) facing each other.
- 2From each hilum, draw a thin tube going down: the ureter.
- 3Join both ureters to a pear-shaped sac at the bottom: the urinary bladder.
- 4From the bladder, draw one short tube: the urethra. At each kidney, label the renal artery and renal vein.
Your own kidneys work like the rabbit's. Drinking enough water in the hot Indian summer helps them flush out urea and lowers the risk of kidney stones.
1 marks: “How many pairs of cranial nerves does a rabbit have?” 12 pairs.
2 marks: “Name the three meninges, from outside in.” Dura mater, arachnoid and pia mater.
4 marks: “Describe the excretory system of the rabbit.” A pair of kidneys with cortex, medulla and nephrons; ureters from the hilum; urinary bladder; urethra; urea as the main waste; a labelled diagram.
Meninges, outside in: 'Don't Ask Papa': Dura, Arachnoid, Pia. Rabbit nerves: 12 cranial pairs, 37 spinal pairs.